U.S. patent application number 14/287896 was filed with the patent office on 2016-09-01 for method for manufacturing a physical volumetric representation of a virtual three-dimensional object.
This patent application is currently assigned to Looking Glass HK Ltd.. The applicant listed for this patent is Looking Glass HK Ltd.. Invention is credited to Tung Yiu Fok, Shawn Frayne, Alexis Hornstein, Shiu Pong Lee.
Application Number | 20160250809 14/287896 |
Document ID | / |
Family ID | 52022849 |
Filed Date | 2016-09-01 |
United States Patent
Application |
20160250809 |
Kind Code |
A1 |
Frayne; Shawn ; et
al. |
September 1, 2016 |
METHOD FOR MANUFACTURING A PHYSICAL VOLUMETRIC REPRESENTATION OF A
VIRTUAL THREE-DIMENSIONAL OBJECT
Abstract
One variation of a method for manufacturing a physical
volumetric representation of a virtual three-dimensional object
includes: receiving a series of adjacent cross-sections of the
virtual three-dimensional object, including a first cross-section
and a second cross-section of the virtual three-dimensional object;
depositing a first layer of transparent polymer; curing a portion
of the first layer of transparent polymer; with ink, printing an
image of the first cross-section onto a dominant face of the first
layer; depositing a second layer of transparent polymer over the
first layer of transparent polymer; curing a portion of the second
layer of transparent polymer; with ink, printing an image of the
second cross-section onto a dominant face of the second layer
according to an order of the series of cross-sections; and
releasing a stack of layers including the first layer of
transparent polymer and the second layer of transparent polymer
from the build platform.
Inventors: |
Frayne; Shawn; (Tampa,
FL) ; Lee; Shiu Pong; (Quarry Bay, HK) ; Fok;
Tung Yiu; (Sha Tin, HK) ; Hornstein; Alexis;
(Raleigh, NC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Looking Glass HK Ltd. |
Kwun Tong |
|
HK |
|
|
Assignee: |
Looking Glass HK Ltd.
Kwun Tong
HK
|
Family ID: |
52022849 |
Appl. No.: |
14/287896 |
Filed: |
May 27, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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61827124 |
May 24, 2013 |
|
|
|
61878789 |
Sep 17, 2013 |
|
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61949070 |
Mar 6, 2014 |
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Current U.S.
Class: |
264/400 |
Current CPC
Class: |
B29C 67/0088 20130101;
B33Y 10/00 20141201; G06T 19/006 20130101; G06T 11/00 20130101;
G06T 2219/2004 20130101; B33Y 40/00 20141201; B29K 2995/0026
20130101; B29C 64/364 20170801; B29C 64/112 20170801; B29C 64/393
20170801; G06T 2219/2008 20130101; B29L 2009/005 20130101 |
International
Class: |
B29C 67/00 20060101
B29C067/00 |
Claims
1. A method for manufacturing a physical volumetric representation
of a virtual three-dimensional object, the method comprising:
receiving a series of adjacent cross-sections of the virtual
three-dimensional object, the series comprising a first
cross-section of the virtual three-dimensional object and a second
cross-section of the virtual three-dimensional object; depositing a
first layer of transparent polymer over a build platform; curing a
portion of the first layer of transparent polymer; with ink,
printing an image of the first cross-section onto a cured exposed
dominant face of the first layer; depositing a second layer of
transparent polymer over the first layer of transparent polymer;
curing a portion of the second layer of transparent polymer; with
ink, printing an image of the second cross-section onto a cured
exposed dominant face of the second layer according to an order of
the series of cross-sections; and releasing a stack of layers
comprising the first layer of transparent polymer and the second
layer of transparent polymer from the build platform.
2. The method of claim 1, wherein receiving the series of adjacent
cross-sections comprises: slicing the virtual three-dimensional
object into a set of virtual adjacent layers of discrete virtual
thickness, the set of virtual layers comprising a first virtual
layer, selecting the first cross-section from within the first
virtual layer, setting a first opacity level of the first
cross-section, and blurring a periphery of the first cross-section
to generate an adjusted first cross-section, and wherein printing
the image of the first cross-section onto the cured exposed
dominant face of the first layer comprises printing an image of the
adjusted first cross-section onto the cured exposed dominant face
of the first layer according to the first opacity level.
3. The method of claim 1, wherein receiving the series of adjacent
cross-sections of the virtual three-dimensional object comprises
slicing the virtual three-dimensional object into a set of virtual
layers of discrete virtual thickness based on a selected resolution
for the physical volumetric representation, the set of virtual
layers comprising a first virtual layer, selecting a set of
adjacent and offset cross-sections, for a series of cross-sections,
of the virtual three-dimensional object contained within the first
virtual layer, setting an opacity level for each cross-section in
the series of cross-sections, and combining the series of
cross-sections into a composite first cross-section based on an
opacity level specified for each cross-section in the series of
cross-sections, and wherein printing the image of the first
cross-section onto the cured exposed dominant face of the first
layer comprises printing a two-dimensional representation of the
first cross-section onto the first layer.
4. The method of claim 1, wherein depositing the first layer of
transparent polymer over the build platform comprises depositing
light-activated resin over a previous layer of transparent polymer,
and wherein curing the portion of the first layer comprises
exposing the dominant face of the first layer to light to cure a
film across the dominant face of the first layer.
5. The method of claim 1, wherein depositing the first layer of
transparent polymer over the build platform comprises depositing a
volume of sugar-based syrup over a previous layer of sugar-based
syrup, and wherein curing the portion of the first layer comprises
evaporating moisture from the volume of sugar-based syrup.
6. The method of claim 5, curing the portion of the first layer
comprises exposing the volume of sugar-based syrup to a heat source
for a preset period of time.
7. The method of claim 1, wherein printing the image of the first
cross-section onto the cured exposed dominant face of the first
layer comprises printing a combination of light-activated cyan ink,
light-activated magenta ink, light-activated yellow ink, and
light-activated black ink onto the cured exposed dominant face of
the first layer, and further comprising exposing the first layer to
light to cure the combination of light-activated cyan ink,
light-activated magenta ink, light-activated yellow ink, and
light-activated black ink.
8. The method of claim 1, wherein printing the image of the first
cross-section onto the cured exposed dominant face of the first
layer comprises printing a first layer of colored ink in the form
of a first image onto the exposed dominant face of the first layer,
printing a second layer of white ink in the form of a second image
over the first layer of colored ink, and printing a third layer of
colored ink in the form of a third image over the second layer of
white ink, the first image, the second image, and the third image
defining components of the first cross-section.
9. The method of claim 8, wherein printing the image of the first
layer of colored ink comprises printing a combination of cyan ink,
magenta ink, yellow ink, and black ink at a first opacity level
onto the dominant face of the first layer, wherein printing the
image of the second layer of white ink comprises printing white ink
at a second opacity level different from the first opacity level
over the first layer of colored ink, and wherein printing the image
of the third layer of colored ink comprises printing a combination
of cyan ink, magenta ink, yellow ink, and black ink at a third
opacity level different from the second opacity level over the
second layer of white ink.
10. The method of claim 1, further comprising etching the exposed
dominant face of the first layer to create pores in the exposed
dominant face of the first layer, wherein printing the image of the
first cross-section onto the cured exposed dominant face of the
first layer comprising printing ink over pores in the exposed
dominant face of the first layer, pores in the exposed dominant
face of the first layer adsorbing ink.
10. method of claim 10, wherein etching the exposed dominant face
of the first layer comprising irradiating the exposed dominant face
of the first layer with a laser beam to create an array of pores in
the first layer at a depth less than a thickness of the first
layer.
12. The method of claim 1, wherein depositing the first layer of
transparent polymer and depositing the second layer of transparent
polymer comprise depositing a sequence of layers of uniform
rectilinear footprint.
13. A method for manufacturing a physical volumetric representation
of a virtual three-dimensional object, the method comprising:
receiving a series of adjacent cross-sections of the virtual
three-dimensional object; for each cross-section in the series of
cross-sections, printing the cross-section over a transparent
portion of a dominant face of one substrate in a set of substrates;
assembling the set of substrates into a stack, each substrate in
the set of substrates positioned within the stack according to a
position within the virtual three-dimensional object of a
cross-section printed on the substrate; drawing a vacuum around the
stack; in the presence of the vacuum, introducing a transparent
fluid to interstices between substrates in the stack, an index of
refraction of the transparent fluid approximating an index of
refraction of a substrate in the set of substrates; and releasing
the vacuum around the stack.
14. The method of claim 13, wherein drawing the vacuum around the
stack comprises calculating a clamping force for the stack based on
a dimension of a substrate in the stack, a material of a substrate
in the stack, and a type of the transparent fluid, clamping the set
of substrates in the stack according to calculated clamping force,
and drawing the vacuum on a pressure vessel containing the stack
for a preset period of time based on a geometry of the stack.
15. The method of claim 14, wherein drawing the vacuum around the
stack comprises drawing the vacuum on the pressure vessel over a
first period of time, and wherein introducing the transparent fluid
to the stack comprises filling a portion of the pressure vessel
with the transparent fluid over a second period of time following
the first period of time.
16. The method of claim 13, wherein printing a cross-section onto a
substrate in the set of substrates comprises printing food-safe ink
onto a translucent sheet of cast sugar.
17. The method of claim 16, wherein introducing the transparent
fluid to interstices between substrates in the stack comprises
introducing water to interstices between substrates in the stack,
and wherein assembling the set of substrates into the stack
comprises compressing the stack under elevated temperature and
substantially normal to a dominant face of a substrate in the
stack.
18. The method of claim 13, wherein receiving the series of
adjacent cross-sections of the virtual three-dimensional object
comprises: slicing the virtual three-dimensional object into a set
of virtual layers of discrete virtual thickness based on a selected
resolution for the physical volumetric representation, and for each
virtual layer in the set of virtual layers, selecting a set of
adjacent cross-sections for a series of cross-sections of a portion
of the virtual three-dimensional object contained within the
virtual layer, setting an opacity level for each cross-section in
the series of cross-sections, combining the series of
cross-sections into a composite cross-section based on an opacity
level set for each cross-section in the series of cross-sections,
and wherein printing the cross-section for each cross-section in
the series of cross-sections comprises printing the composite
cross-section onto a transparent portion of a dominant face of a
substrate in the set of substrates for each virtual layer in the
set of virtual layers.
19. The method of claim 13, wherein printing a cross-section over a
substrate in the set of substrates for each cross-section in the
series of cross-sections comprises printing, in ink, an image of a
first cross-section in the series of cross-sections onto a first
substrate in the set of substrates, the first substrate comprising
an array of pores, of depth less than a thickness of the first
substrate, across a dominant face of the first substrate.
19. The method of claim 19, further comprising molding the first
substrate in a transparent polymer defining an array of pores
across a dominant face.
21. The method of claim 13, further comprising forming a bore in a
substrate in the set of substrate and installing a magnetic element
into the bore in the substrate assembled into the stack, the stack
coupling to a second stack by the magnetic element.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This applications claims priority to U.S. Provisional
Application No. 61/827,124 filed on 24 May 2013, U.S. Provisional
Application No. 61/878,789 filed on 17 Sep. 2013, and to U.S.
Provisional Application No. 61/949,070 filed on 6 Mar. 2014, all of
which are incorporated in their entireties by this reference.
TECHNICAL FIELD
[0002] This invention relates generally to the field of
three-dimensional imaging, and more specifically to a new and
useful method for manufacturing a physical volumetric
representation of a virtual three-dimensional object in the field
of three-dimensional imaging.
BRIEF DESCRIPTION OF THE FIGURES
[0003] FIG. 1 is a flowchart representation of a first method of
the invention;
[0004] FIG. 2 is a flowchart representation of a second method of
the invention;
[0005] FIG. 3 is a flowchart representation of a third method of
the invention;
[0006] FIGS. 4A, 4B, and 4C are graphical representations of
variations of the methods;
[0007] FIGS. 5A, 5B, 5C, and 5D are graphical representations of
one variation of the methods;
[0008] FIG. 6 is a graphical representation of one variation of the
methods;
[0009] FIGS. 7A, 7B, and 7C are schematic representations of one
variation of the first method;
[0010] FIG. 8 is a schematic representation of one variation of the
first method;
[0011] FIG. 9 is a flowchart representation of one variation of the
third method.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0012] The following description of the preferred embodiment of the
invention is not intended to limit the invention to these preferred
embodiments, but rather to enable any person skilled in the art to
make and use this invention.
1. First Method: Discrete Layers and Applications
[0013] As shown in FIG. 1, a method S100 for manufacturing a
physical volumetric representation of a virtual three-dimensional
object includes: receiving a series of adjacent cross-sections of
the virtual three-dimensional object in Block S110; for each
cross-section in the series of cross-sections, printing the
cross-section over a transparent portion of a dominant face of one
substrate in a set of substrates in Block S140; assembling the set
of substrates into a stack, each substrate in the set of substrates
positioned within the stack according to a position within the
virtual three-dimensional object of a cross-section printed on the
substrate in Block S160; drawing a vacuum around the stack in Block
S170; in the presence of the vacuum, introducing a transparent
fluid to interstices between substrates in the stack, an index of
refraction of the transparent fluid approximating an index of
refraction of a substrate in the set of substrates in Block S180;
and releasing the vacuum around the stack in Block S190.
[0014] Generally, the method S100 can be implemented in manufacture
of a three-dimensional volumetric "print" exhibiting a
three-dimensional graphic representation of an object or multiple
objects, such as a scene, in physical space, as shown in FIGS. 5A
and 5D. In particular, the method S100 can be executed to slice a
virtual three-dimensional model into cross-sections, to print--in
ink--images of the cross-sections onto transparent substrates e.g.,
sheets), to stack the transparent substrates with images printed
thereon in alignment, as shown in FIG. 5B and 5C, and to fill
interstices between adjacent substrates in the stack with a
transparent fluid exhibiting an (average) index of refraction (or
Abbe number and/or other optical property) approximating that of
the substrates, thereby reducing internal reflection of light
through stack of substrates. The series of cross-sectional images
printed on sequential substrates in the stack can thus visually
approximate the form of the virtual object(s) in real (i.e.,
physical) space, and this substantially intransient
three-dimensional representation can be viewed from outside of the
stack by multiple viewers simultaneously and with the naked
eye.
[0015] The method S100 can thus be implemented to replace volumes
between substrates within the stack and gas (e.g., air) pockets
trapped within the stack with an "index-matching" fluid, thereby
increasing optical uniformity throughout the volume of stack
outside of the physically-represented virtual object and increasing
visibility through the stack to the physically represent virtual
object. The method S100 can also control opacity levels for
cross-section images printed on a series of substrates such that a
three-dimensional representation of a virtual object exhibits some
translucency, thereby enabling a view to see through real "object"
represented within the stack and/or enabling the object to be
illuminated within the stack via a light source outside the stack.
In particular, by controlling opacity (or translucency) of printed
cross-section images, the method S100 can generate a physical
three-dimensional representation of a virtual object that preserves
color of the virtual object throughout the entire depth of the
virtual object and that enables a viewer to visually access this
color information throughout the depth of the physical
representation of the virtual object.
[0016] In one example, the method S100 can be executed to print an
archival three-dimensional "image" of an object (e.g., a frog
skeleton) or a scene (e.g., race track with three-dimensional
representations of cars in position on the track at a particular
instance during a race). In another example, the method S100 is
executed to generate a stack containing a three-dimensional
representation of a medical procedure, such as a translucent
three-dimensional representation of a patient's brain--with a
cancer mass shown in a distinct color--based on virtual object of
the patient's brain generated from a CAT scan. In yet another
example, the method S100 is executed to generate multiple stacks,
each containing a three-dimensional representation of an
architectural structure, throughout a design phase of a project. In
these examples, the method S100 can selectively move cross-sections
of the object(s) or scene to be represented between being in-focus
and being out of focus to control definition (or perceived
importance) of objects or regions of objects represented within the
stack.
[0017] Such a stack generated through application of the method
S100 can also be backlit to control visibility of "object"
represented in ink in three dimensions within. For example, the
stack can be illuminated with a lighting system built into or
arranged in proximity to the stack, such as one or more OLED layers
arranged across one external surface of the stack. In this
implementation, Block S140 can print--onto substrates in the
stack--portions of images of cross-sections of a virtual object in
fluorescent ink such that additional visual content may be accessed
by a user by exposed the stack with a fluorescent light source.
However, the method S100 can be used in any other application to
generate a physical three-dimensional representation of a virtual
object.
[0018] From herein after, "virtual model" will refer to any virtual
object, set of virtual objects, or scene, and "physical model" will
refer to any assembly of substrates and (printed) ink layers
defining a physical volumetric representation of a virtual
model.
1.1 Cross-Sections
[0019] Block S110 of the method S100 recites receiving a series of
adjacent cross-sections of the virtual three-dimensional object.
Generally, Block S110 functions to collect and/or generate a series
of cross-sections corresponding to a virtual model to be
represented in physical space by printing images of the cross
sections on a set of substrates in Block S140, stacking the set of
substrates in Block S160, and finishing the stack in Block S190.
For example, Block S110 can execute with Block S140 on a printing
machine to upload images of cross-sections subsequently printed
onto substrates in Block S140. Alternatively, Block S110 can be
implemented within a computer-aided drafting (CAD) software
executing on a laptop of desktop computer extract cross-sections
from a three-dimensional CAD model of an object or scene
constructed virtually within the CAD software. Yet alternatively,
Block S110 can be implemented within a standalone three-dimensional
printing application executing on a computing device (e.g., a
laptop or desktop computer, a smartphone, a tablet etc.) to import
a digital file of a virtual object, to extract cross-sections from
the virtual object, and to upload images of the cross-sections to a
(external) printing machine.
[0020] As described above, the virtual model can include one or
more virtual objects with or without virtual internal features. For
example, the virtual model can include a computer-generated
three-dimensional virtual object, such as a solid three-dimensional
CAD model of a chair including modeled internal cushion materials
and fasteners. In this example, the virtual model can also include
a solid three-dimensional CAD model of a human sitting in the chair
and exhibiting with color-real skin, facial features, and clothing
but without representation of internal organs. Furthermore, in this
example, the virtual model can include a virtual cigarette in the
virtual humans hand and a virtual wisp of smoke rising from the
virtual cigarette. Block S110 can thus receive or populate (e.g.,
generate from the virtual model) a sequence of cross-sections
representing internal and external features of the chair, external
features and colors of the human and the cigarette, and "specks"
representation the virtual wisp of smoke and with specific opacity
levels set for each corresponding region of each cross-section.
Subsequent Blocks of the method S100 can thus yield a real model
(i.e., a volumetric print) of the "scene" in physical space,
wherein internal structures of the chair is visible, the human is
represented in substantially true color, and the cigarette smoke is
evident in the real scene. However, Block S110 can receive or
generate cross-sections of any other type of object, objects, or
scenes.
[0021] In one implementation, the method S100 generates a
rectilinear (e.g., cubic) stack of transparent substrates with
non-linear cross-sections of an organic (i.e., non-linear) virtual
model printed onto a subset of the substrates within the stack,
thereby yielding an impression a the representation of the virtual
model "floats" within the stack. In this implementation, the stack
can be composed of a set of substrates defining rectilinear sheets
of transparent material of substantially uniform thickness across a
substrate and throughout the set of substrates, and the stack can
exhibit a substantially uniform center-to-center distance between
adjacent substrates throughout the stack. To create a stack as in
this implementation, Block S110 can receive a digital model of a
virtual model (e.g., a virtual sphere), as shown in FIG. 4A,
specify a series of parallel (i.e., nonintersecting) virtual planes
intersecting the virtual model and offset by a virtual distance
corresponding to the real center-to-center distance between
adjacent substrates that such a stack would exhibit, as shown in
FIG. 4B, and then capture a cross-section of the virtual model at
the intersection of each virtual plane with the virtual model. In
this implementation, Block S110 can capture cross-sections that are
color-true to the virtual model, that include both external lines
(of some thickness) coinciding with a shell of the virtual model,
and that include points, lines, and/or areas representing virtual
internal features of the virtual model. Block S110 can thus select
a series of discrete cross-sections of the virtual model coinciding
with parallel and offset virtual planes passing through the virtual
model.
[0022] In the foregoing implementation, Block S110 can also receive
any one or more parameters controlling a selection of
cross-sections from the virtual model, such as target
center-to-center distance between (real) substrates in the physical
volumetric representation, substrate thickness, real model
resolution, real model scale, etc. For example, Block S110 can
receive from a user a selection for a real model type in which
adjacent substrate layers are bonded together with a think adhesive
film, a selection for a substrate sheet material thickness of 0.5
mm, and a maximum width dimension of 80 mm for a physical
representation of a virtual object, such as through a user
interface shown in FIG. 6. In this example, Block S110 can also set
or receive an object boundary offset value (i.e., a minimum
distance between the physical representation of the virtual model
with the stack to an outer surface of the stack, or a minimum
distance between an edge of a substrate and an border of an image
printed on the substrate) at 10 mm. Thus, Block S110 can calculate
a number of slices through the virtual model according to the
function:
n=[real width]/[center-to-center distance]=80 mm/0.5 mm=160. [0023]
Block S110 can thus define 160 parallel and evenly-spaced virtual
planes through the virtual object and capture a cross-section of
the virtual model at the intersection of each planes through the
virtual model. In this example, Block S110 can specify 160 discrete
substrates onto which one image of each of the 160 cross-sections
will be printed, twenty blank substrates of the same footprint that
are to be assembled over an `inked` substrate on one side of the
stack, and another twenty blank substrates of the same footprint
that are to be assembled over a printed substrate on one side of
the stack (in order to achieve the object boundary offset
requirement).
[0024] Block S110 can additionally or alternatively receive from
the user a selection for a resolution of the virtual object
depicted in the real model. For example, Block S110 can receive a
maximum (virtual or real) step size between cross-sections in the
(virtual or real) model or a maximum ratio of step size to a
dimension of the (virtual or real) model along an axis of the model
normal to the parallel and offset planes. Block S110 can then
implement this selection(s) to select an available substrate
material thickness from a list of available substrate sheet
materials, to set a substrate thickness, to define a target offset
between inked substrates (i.e., a target center-to-center distance
to be filled with index-matching fluid or filler panels), etc. For
example, Block S110 can set a default center-to-center distance
between adjacent substrates and capture cross-sections at a
corresponding number of planes within the virtual model, as shown
in FIG. 4B, and Block S110 can then set increase the
center-to-center distance between adjacent substrates and capture a
greater number of cross-sections at corresponding planes within the
virtual model, as shown in FIG. 4C.
[0025] However, Block S110 can receive a selection for one or more
of the foregoing and/or other parameters to control selection of
discrete cross-sections of the virtual model through the thickness
of the virtual mode.
1.2 Printing Cross-Sections
[0026] Block S140 of the method S100 recites, for each
cross-section in the series of cross-sections, printing the
cross-section over a transparent portion of a dominant face of one
substrate in a set of substrates. Generally, Block S140 functions
to print an image of one cross-section in the set of cross-sections
on each substrate in the set of substrates such that, when the
substrates are stacked in Block S160, the images of cross-sections
yield a three-dimensional representation of a virtual object in
physical space.
[0027] Block S140 thus controls selective deposition of one or more
colors of ink--in the form of images of cross-sections of the
virtual model--onto real substrates. In various examples, Block 140
can interface with an ink jet printer to deposit fluid ink onto
substrates, with a laser print to deposit and fuse toner onto
substrates, or with an LED electrostatic toner-based printer to
deposit and fuse toner onto substrates. Alternatively, Block S140
can interface with a laser etching apparatus supporting a secondary
inking process, a xerographic printing or reproduction apparatus, a
screen-printing apparatus, or a pen plotting apparatus to control
deposition of ink, toner, or other media (from herein after "ink")
onto substrates. Block S140 can control deposition of black ink,
white ink, and/or colored inks (e.g., cyan, magenta, and yellow
inks; red, yellow, and blue inks) onto substrates in the stack,
such as based on color value stored in the cross-sections of the
virtual model or based on inks supported by the printing apparatus
in use. For example, Block S140 can include printing a combination
of light-activated cyan ink, light-activated magenta ink,
light-activated yellow ink, and light-activated black ink (i.e.,
CMYK inks) onto a face of a substrate and then expose the substrate
to ultraviolet light to cure the combination of light-activated
cyan ink, light-activated magenta ink, light-activated yellow ink,
and light-activated black ink. Block S140 can also control
deposition of inks containing metallic, ceramic, diamond, or other
particulate onto substrates, such as a yield a pearlescent
appearance to a modeled surface within the real model. However,
Block S140 can control printing of any other suitable type of ink
onto a substrate.
[0028] Block S140 prints ink representative of cross-sections of
the virtual model onto transparent substrates such that ink printed
on a particular substrate is visible through adjacent substrates
when the set of substrates is assembled into a stack. For example,
substrates can be of acrylic (e.g., polymethyl methacrylate, or
PMMA), polyethylene terephthalate (PET), polypropylene (PP),
polyethylene (PE), polycarbonate (PC), curable resin, poly(vinyl
chloride) PVC), glass, polyester, vellum, cellulose, sugar, amber,
ice, glass, acetate, solidified wax (e.g., paraffin), or other
transparent or suitably translucent material. In one example
implementation, Block S140 deposits colored toner
electrostatically--in the form of images of cross-sections of the
virtual model--onto corresponding discrete sheet sheets of PMMA of
substantially uniform thickness. In another example implementation,
Block S140 interfaces with a print head to deposit food-safe
colored ink--in the form of images of cross-sections of the virtual
model--onto translucent sheets of cast sugar, such as cast sheets
of isomalt or a mixture of white sugar and cream of tartar, to form
an edible stack containing a physical representation of the virtual
model within.
[0029] Furthermore, each substrate in the real model can be of the
same or different material and/or substantially identical or
differing translucency or color, etc. For example, the stack can
include a subset of substrates clear material and a subset
substrates of tinted (e.g., red) material (i.e., the substrate is
of uniform tint throughout its thickness), and tinted substrates
can be interposed between clear substrates to form the stack in
Block S160, such as to yield a uniform tinted "glow" of controlled
opacity throughout the real without necessitating deposition of ink
across a larger surface of the substrates to mimic the tint.
Alternatively, in this example, the set of clear substrates can be
stacked together, and the set of tinted substrates can be stacked
together and arranged adjacent the stack of clear substrates to
mimic a shadow over a portion of a scene represented within the
real model without necessitating deposition of ink across a larger
surface of the substrates to mimic the tint. A substrate can also
exhibit uniform optical properties (e.g., transparency and tint)
throughout its volume, or a substrate can exhibit a transparent
portion and an opaque portion (or a portion that is other than
clear and transparent), and Block S140 can thus print selectively
over the transparent portion of the substrate or over both the
transparent and opaque portions of the substrate according to a
desired opacity of ink deposited to the substrate.
[0030] Based on a material type selected for the real model, Block
S140 can also activate a surface of a substrate onto which ink is
to be deposited. For example, acetate-based substrate may exhibit a
relatively high surface energy that readily accepts ink, whereas
ink deposited onto an untreated acrylic substrate may be less
stable. Therefore, for an acrylic substrate, Block S140 can include
modifying a surface of the substrate with a corona treatment, by
etching the surface with a laser, or roughing the surface with an
abrasive such that ink subsequently printed onto the surface is
more stable on the substrate. In this variation, Block S140 can
print ink--in the form of a cross-section of the virtual
model--onto an activated (i.e., high-surface-energy) surface of a
substrate and then expose the ink and the substrate to UV light to
bond the ink to the surface of the substrate. In another example,
Block S140 deposits a coating onto a dominant face of a substrate
and then prints ink--in the form of a cross-section of the virtual
model--onto the coating, which bonds with the ink to retain the
image. However, Block S140 can prepare a surface of the substrate
for deposition of ink thereonto in any other suitable way.
[0031] In one implementation, Block S140 prints images onto sheets
of material of substantially uniform thickness, such as sheets of
PMMA 0.3 mm in thickness, and substrates of such substantially
uniform thickness can thus be assembled linearly along an axis
(e.g., vertically, horizontally) in Block S160 to form the stack.
In this implementation, Block S140 can print images onto pre-cut
sheets (i.e., substrates) such that the substrates can be assembled
into the stack substantially immediately following completion of a
deposition of ink thereonto in Block S140. Alternatively, Block
S140 can print an image of a cross-section onto an oversized sheet
and subsequently trim the oversized sheet down to an appropriate
size, as shown in FIG. 1. For example, a one-meter wide, 100-meter
long roll of 0.3 mm-thick cellulose acetate can be loaded into a
processing center (e.g., a single machine, a collection of
processing machines), and Block 140 is executed by the processing
center to unroll a 110 mm-long section of cellulose acetate roll,
to apply a corona treatment across the width of the 110 mm-long
section in 10 mm step increments, to print (with an ink print head)
nine distinct cross-sections within nine laterally adjacent 100
mm-wide by 100 mm-long areas spaced apart by 9 mm across the width
of 110 mm-long section the cellulose acetate roll, to cure the ink
printed across the roll, and to then cut (e.g., with a laser or a
blade) each of the nine 100 mm-wide by 100 mm-long areas (now with
ink) within the 110 mm-long section of cellulose acetate roll,
thereby releasing nine completed 100 mm-by-100 mm substrates, each
with an image of a cross-section printed thereonto.
[0032] Therefore, as in the foregoing implementation, the method
S100 can generate a real model with external boundaries that extend
beyond the bounds of a representation of a virtual object contained
within the real model. For example, the virtual model can define a
single sphere, and the real model can be a cubic stack of
substrates, wherein each substrate in the stack is of a discrete
thickness (e.g., between 0.3 mm and 5 mm) and defines a
substantially identical square footprint such that the virtual
sphere represented in physical space within the stack is fully
contained within the cubic real model. Alternatively, Block S140
can interface with a processing apparatus (e.g., a laser cutter, a
vinyl cutter) to trim each substrate around an image of a
cross-section previously printed thereon before the substrates are
assembled into a stack in Block S160 such that the completed real
model is of a physical form representative of the virtual object.
Similarly, Block S140 can interface with a cutting apparatus to cut
a substrate to a tracing a perimeter of an image of a cross-section
(soon) to be printed on the substrate. However, Block S140 can cut
each substrate in the set of substrates into any other form and
with any other process to yield a real model of any suitable
three-dimensional form upon assembly of the substrates in Block
S160, and Block S140 can print any other number of images of
discrete cross-sections onto individual, discrete substrates in any
other way.
[0033] In another implementation, Block S110 receives or generates
a single spiral cross-section of the virtual object, wherein the
spiral of the cross-section defines an Archimedean spiral of
function r=.alpha.+b.theta., wherein b equals a target
center-to-center distance between turns of the spiral. Thus, in
this example, Block S110 can flatten the spiral cross-section into
a two-dimensional image, Block S140 can print the two-dimensional
image onto a single continuous substrate, and Block S160 can roll
the substrate into a cylinder according to the same
r=.alpha.+b.theta. function. However, Block S140 can print any
other continuous (e.g., spiral) cross-section on any other number
of substrates that are later assembled in Block S160 to form a
stack, and the substrates can be of any other form (e.g.,
triangular in cross-section) and can define any other suitable
footprint.
[0034] Generally, Block S140 prints an image of a cross-section
onto a broad surface (i.e., a "dominant face") of a substrate
exposed to a print head, silk-screen, etc. For example, "dominant
faces" of a substrate can be defined as the two surfaces of the
substrate of greatest surface area, wherein a dominant face of one
substrate faces a dominant face of an adjacent substrate, such as
in contact with the dominant face of the adjacent substrate or
offset from the dominant face of the adjacent substrate with fluid
or a filler panel arranged therebetween, the separation distance
between facing dominant faces being determined by the surface
tension of the filling fluid, pressure between and surrounding the
substrate, and other electrostatic forces. Block S140 can thus
print a singe image of a cross-section onto one dominant face of
substrate before the substrate is added to a stack of other
substrate in Block S160. Block S140 can also print a sequence of
images of different cross-sections over a single dominant face of a
substrate. For example, Block S110 can "slice" a virtual model into
1000 layers and capture a cross-section of the virtual model at
each of the 1000 layers. However, in this example, the real model
can include only 200 substrates, and Block S140 can thus print one
image of each of five sequential cross-sections of the virtual
model onto a single dominant face of each substrate in the set of
200 substrates, such as to increase a perceived resolution of the
physical representation of the virtual model in the stack. Block
S140 can additionally or alternatively print on both images of
cross-sections of the virtual model onto both sides of a substrate,
that is, onto both dominant faces of the substrate. For example,
Block S140 can print onto a first dominant face of a substrate one
image of a first cross-section of the virtual model and then print
onto a second dominant face of the substrate an image of second
cross-section adjacent the first cross-section in the virtual
model.
[0035] Block S140 can also print ink that is removable from
substrates, such as to enable the real model to be recycled and
substrates reused in a real model of another object or scene. For
example, Block S140 can print removable ink onto substrates such
that the ink can be mechanically scraped or chemically removed from
each substrate in the stack once a useful life of the real model
expires. However, Block S140 can function in any other way to print
images of cross-sections of a virtual model onto transparent
portions of dominant faces of substrate in a set of substrates.
1.3 Stacking Substrates
[0036] Block S160 of the method S100 recites assembling the set of
substrates into a stack, each substrate in the set of substrates
positioned within the stack according to a position within the
virtual three-dimensional object of a cross-section printed on the
substrate. Generally, Block S160 functions to order a set of
substrates--each with one or more images of cross-sections of the
virtual model applied thereon--into a stack with adjacent images of
cross-sections substantially aligned such that a sensible
representation of the virtual model is visually discernible within
the physical stack.
[0037] In one implementation of Block S160, substrates are stacked
with dominant faces in contact with each other. In this
implementation, small gaps may exist between regions of adjacent
substrates, such as due to small deviations across the dominant
face and/or a thickness of the substrates, and Blocks S170, S180,
and S190 can thus cooperate to replace air in such gaps with a
fluid exhibiting an index of refraction that better matches that of
the substrate material.
[0038] In another implementation of Block S160, substrates are
offset in a stack with a particular offset distance (i.e., a
particular center-to-center) distance between adjacent substrates.
For example, in Block S160, substrates can be installed in a rack
(or frame) with tabs that retain each substrate at a particular
offset distance from adjacent substrates. Thus, in this
implementation, Blocks S170, S180, and S190 can cooperate to
replace air between each substrate with a fluid exhibiting an index
of refraction that better matches that of the substrate
material.
[0039] In a similar implementation of Block S160, transparent
filler panels (i.e., blank substrates) are interposed between
substrates to fill volumes between adjacent images of
cross-sections of the virtual model within the stack. For example,
Block S140 can print images of cross-sections onto 100 0.3 mm-thick
transparent PMMA substrates, and each of the 100 substrates can be
interposed between two of 101 0.2 mm-thick transparent acrylic
filler panels in Block S160 to create a .about.500.2 mm-thick
stack. As in a preceding implementation, gaps may exist between
portions of a substrate and an adjacent filler panel, and Blocks
S170, S180, and S190 can thus cooperate to replace air in such gaps
with a fluid exhibiting an index of refraction that better matches
that of the substrate material. Therefore, a number of printed
substrates for a volumetric printed stack of a selected depth
resolution can be substantially decreased by assembling the
substrates with a center-to-center distance between substrates that
is substantially greater than a thickness of each substrate.
[0040] In Block S160, the substrates can also be arranged within a
frame or a casing that maintains the substrates in alignment, and
the casing can be subsequently sealed in Block S190 to prevent
egress of index-matching fluid from the stack, as described below.
However, the substrates can be aligned, assembled, and/or retained
in a stack in any other suitable way in Block S160.
1.5 Index-Matching
[0041] Block S170 of the method S100 recites drawing a partial
vacuum (from herein after "vacuum") around the stack, Block S180 of
the method S100 recites, in the presence of the vacuum, introducing
a transparent fluid to interstices between substrates in the stack,
an index of refraction of the transparent fluid approximating an
index of refraction of a substrate in the set of substrates, and
Block S190 of the method S100 recites releasing the vacuum around
the stack. Generally, Blocks S170, S180, and S190 cooperate to
replace air (and/or other gases) between dominant faces of adjacent
substrates within the stack (and printed mages on the substrates)
with a fluid exhibiting optical properties (e.g., index of
refraction, Abbe number, etc.) that better match those of the
substrate material, thereby reducing internal reflection of light
within substrates in the state, increasing total transparency of
the stack, and yielding a stack that more closely visually
approximates a continuous material throughout its volume. For
example, without an index-matching material, a stack of substrates
may appear substantially opaque due to reflections at boundary
layers of adjacent substrates, and a scene represented within the
stack may therefore not be viewable. However, by filling
interstices between substrates in the stack, Blocks S170, S180, and
S190 can reduce internal reflections within the stack, thereby
increasing transparency of the stack to yield a representation of
the virtual model that is visible from outside the stack.
[0042] Regions between adjacent substrates and/or between
substrates and adjacent filler panels can therefore be filled with
a suitable index-matching material, such as water (e.g., distilled
water, salt water), ice, oil (e.g., baby oil, silicone oil), a gel,
wax (e.g., mineral oil-based gel wax), or an adhesive (e.g.,
UV-cured transparent adhesive), etc., such as through pouring,
pumping, wiping, capillary action, or bulk injection, etc. A vessel
(or frame, etc.) containing the stack can be filled with the same
or similar index-matching material such that the index-matching
material fills interstices between substrates in the stack and
interior surfaces of the vessel. In particular, the fluid can fill
volumes between the stack and the vessel containing the stack to
enable visibility of the representation of the virtual model within
from substantially 360.degree. about the vessel. The index-matching
material can also be cured, hardened, or dried from a fluid to a
solid or from a fluid of one viscosity to a fluid of a higher
viscosity.
[0043] The index-matching material can exhibit an index of
refraction, an Abbe number, and other optical property that
substantially matches that (or those) of the substrate material,
filler material, and/or ink, etc. such that the physical
representation of the virtual model within the completed stack can
be seen by a user at relatively high viewing angles. Alternatively,
the index-matching material can exhibit an index of refraction that
is (slightly) greater than an index of refraction of the substrate
material to substantially the completed stack from forming a total
internal reflection light guide, that is, to prevent the completed
stack from "light locking" at certain viewing angles. Similarly,
the index-matching material can exhibit an index of refraction that
is less than an index of refraction of the substrate material to
reduce edge reflections within the completed stack at certain
viewing angles.
[0044] The index-matching material can remain substantially fluid
throughout a lifespan of the stack, such as for an index-matching
material that includes water or silicone oil. Alternatively, the
index-matching material can be applied over dominant faces of
substrates before assembly or drawn into the assembled stack as a
fluid that changes phase to a solid once the stack is assembled.
For example, a transparent wax can be heated to transition the wax
from a solid into a liquid, the wax injected between adjacent
substrates in the stack, and the stack then cooled to harden the
wax into a solid. The index-matching material can also function to
retain adjacent substrates in position. For example, the
index-matching material can include a light-curing adhesive that is
substantially transparent when cured, and the adhesive can be
spread across dominant faces of the substrates, the substrates
assembled and aligned in a stack, the stack compressed--normal to
the dominant faces of the substrates--in a fixture to press excess
adhesive from the stack, the stack degassed in a pressure vessel,
and the stack exposed to ultraviolet light to cure the
adhesive.
[0045] The index-matching material can also be selected based on
other material properties of the substrate material and/or the
filler panel material. For example, silicone oil can be selected
for glass substrates but not for PMMA or urethane substrates to a
tendency of PMMA and urethane to absorb silicone oil.
[0046] In one implementation, index-matching material is applied to
dominant faces of the substrates in Block S180 prior to assembly of
the stack in Block S160, such as by printing ink and then printing
index-matching material onto a dominant face of a substrate,
spraying index-matching material onto a substrate, dripping or
wiping the index-matching material onto each substrate, exposing
each substrate to a gaseous form of the index-matching material, or
setting a sheet of index-matching gel over a dominant face of a
substrate. In this implementation, the stack--now with
index-matching material arranged between substrates--is set inside
a pressure vessel and a vacuum is drawn on the stack in Block S170
to draw any remaining gas (e.g., air) from the stack, to outgas the
substrates, and/or to outgas the index-matching material. For
example, the stack can be held at vacuum within the pressure vessel
for a period of time based on a viscosity of the index-matching
material in Block S170 (i.e., to ensure that gas can move out of
interstices between substrates), wherein stacks containing less
viscous index-matching materials are held in vacuum for a period of
time (e.g., two minutes) short than stacks containing more viscous
index-matching materials (e.g., twenty-four hours). Similarly, a
stack containing more volatile index-matching material or
substrates of a more volatile material can be outgassed for
extended periods of time in Block S170 to reduce opportunity for
the index-matching material and/or the substrates to later outgas
into interstices between substrates, which could otherwise yield
gaseous pockets that obstruct visibility through the stack.
Furthermore, as in the example described above in which the
substrates are assembled in a stack and then compressed normal to
the dominant faces of the substrates, vacuum can be drawn on the
stack in Block S170 for a period of time based on a mechanical
pressure between substrates. Similarly, the stack can be exposed to
vacuum within the pressure chamber in Block S170 for a period of
time based on a dimension (e.g., a maximum dimension) of the stack.
For example, Block S170 can implement a parametric model to
calculate a vacuum time based on a maximum width dimension and a
maximum length dimension of a dominant face of a substrate in the
stack.
[0047] In one example of the foregoing implementation Block S140
deposits food-safe ink onto substrates of cast sheets of sugar,
water, alcohol, or an other food-safe transparent liquid capable of
superficially dissolving the substrates is deposited onto broad
faces of the substrates in Block S180 as the substrates are
arranged into a stack in Block S160. The stack can then be
compressed normal to a dominant face of a substrate in the stack,
such as under elevated temperature to superficially melt adjacent
dominant faces of the substrates, thereby forming a substantially
continuous volume of translucent solidified sugar with colored
ink(s) contained within to yield a physical representation of the
virtual model.
[0048] In another example of this implementation, the
index-matching material of a known viscosity is applied to dominant
faces of the substrates, and the substrates are assembled into the
stack such that offset distances between adjacent dominant faces of
the substrates is controlled by the index-matching material
according to surface tension and viscosity of the index-matching
material. In this example, the stack can also be compressed--normal
to the dominant faces of the substrates--up to a specified pressure
to control offset distances between adjacent dominant faces of the
substrates.
[0049] In another implementation, the stack is assembled "dry"
(i.e., without index-matching material) in Block S160, and the
stack is then placed within a pressure vessel. A vacuum is then
drawn on the pressure vessel over a first period of time (e.g.,
twenty seconds to twenty-four hours) in Block S170, and a portion
of the pressure vessel is filled with a transparent index-matching
fluid in Block S180 once the first period of time expires. With
vacuum maintained within the pressure vessel, the fluid is then
drawn into interstices between substrates over time via capillary
action. As described above, the vacuum can be maintained over the
stack to further degas the substrates and/or the fluid.
[0050] In this implementation, the substrates can be set in a form
(e.g., a frame) that maintains the offset distance between dominant
faces of adjacent substrates in the stack. For example, the
substrates can be placed in a five-sided casement defining a series
of tracks that retain the substrates in position, such as shown in
FIG. 8. Furthermore, in this example, the casement can include a
lid that is sealed (e.g., by gluing, by polymer seal) over an
opening of the casement to fully enclose the stack of substrates
within. The lid can also define a fill port through which
index-matching material can be injected into or introduced to the
stack, as shown in FIG. 8. Alternatively, a (porous) coating can be
applied to dominant faces of the substrates, wherein the coating is
of thickness that is half a target offset distance between adjacent
substrates to maintain the offset distance between adjacent
substrates when the stack is assembled. For example, the coating
can yield an array of bumps on each substrate. In another example,
the coating can include grains of microspheres deposited onto each
substrate. Similarly, the substrates can be etched (prior to
printing images thereon in Block S140) to form troughs and ridges
such that, when the stack is assembled, adjacent substrates form
conduits (e.g., "veins") of appropriate cross-section to wick fluid
through fully across the junction between adjacent substrates. Yet
alternatively, the stack can be compressed normal to dominant faces
of the substrates, such as based on a surface area of the dominant
faces, to control contact (or offsets) between dominant faces of
adjacent substrates. For example, Block S180 can calculate a
clamping force for the stack based on a dimension of a substrate in
the stack, a material of a substrate in the stack, and a type of
the transparent fluid, and the stack can be clamped according to
calculated clamping force in Block S160 prior to introduction of
the index-matching material to the stack in Block S180.
[0051] In a similar implementation, Blocks S170, S180, and S190 can
be implemented by a bulk injection system including a pressure
vessel, a reservoir containing index-matching fluid (e.g., water,
adhesive, gel), a solenoid for controlling flow of index-matching
fluid into the pressure vessel, and a vacuum pump for drawing
vacuum on the pressure vessel, as shown in FIGS. 7A, 7B, and 7C. In
this implementation, index-matching fluid within the reservoir can
be degassed to lower an amount of dissolved air within the fluid,
and the assembled (dry) stack of substrates can then be placed on a
titled platform inside the pressure vessel with a particular corner
of the stack defining a highest vertical point within the system,
as shown in FIGS. 7B and 7C. The solenoid is then tripped to
release degassed index-matching fluid from the reservoir into the
pressure vessel to immerse the stack in index-matching fluid. For
example, the reservoir can be connected direction to a stack via a
supply line connected to a fill port in a casement containing the
stack of substrates, as shown in FIGS. 7C and 8. In another
example, the volume around the stack within the pressure vessel is
flooded with the index-matching material. The pressure vessel is
subsequently sealed and a vacuum drawn on the pressure vessel by
the vacuum pump in Block S170 to draw air (and other gases) out of
the stack. After a suitable period of time, the pressure vessel is
opened to ambient pressure, thereby forcing index-matching fluid
into interstices between adjacent substrates in the stack in Block
S180. This process of drawing and releasing vacuum on the stack in
the presence of index-matching fluid can be repeated to force
additional index-matching fluid into the stack. Eventually, the
index-matching fluid can be drained from the pressure vessel and
the stack removed in Block S190.
[0052] Upon completion of a vacuum period, the atmospheric pressure
can be established within the pressure vessel and the stack then
removed from the pressure vessel in Block S190. Alternatively, upon
completion of the vacuum period, positive pressure can be
established within the pressure vessel and the periphery of the
stack sealed such that contents (i.e., the substrates, the
index-matching material) within the stack are sealed within a
positive pressure atmosphere, thereby inhibiting outgassing of the
contents of the stack and reducing opportunity for gas pockets to
form between substrates within the stack over time. For example,
for a stack filled with a silicone oil index-matching material, the
stack can be sealed with positive internal pressure that inhibits
phase change of the silicone oil from liquid to gas.
[0053] Furthermore, as described above, the index-matching material
can include a curable adhesive or a resin. For example, the
index-matching material can be UV-curable resin, and the stack can
thus be exposed to UV light upon removable of the stack from the
pressure vessel, thereby curing the resin. In another example, the
index-matching material can be an adhesive that cures at elevated
temperature, and the stack can thus be placed in an oven or an
autoclave to active and cure the adhesive. However, the
index-matching material can be cured in any other way--during or
after the vacuum process--to retain substrates (and filler panels)
in position in the stack.
[0054] In another example in which Block S140 deposits food-safe
ink onto substrates of cast sheets of sugar, the stack of
sugar-based substrates can be stacked in Block S160, the stack can
be placed in a vacuum chamber and a (partial) vacuum drawn on the
stack, and a volume of water, alcohol, or other food-safe
transparent liquid can be introduced to the stack under vacuum in
Block S180, as described above. Thus, as the fluid is draw between
interstices between adjacent substrates, the water, alcohol, or
other fluid can dissolve sugar crystals along dominant faces of the
substrates. However, as the water, alcohol, or other fluid
evaporates from the stack, dissolved sugar molecules recrystallize
across interstices between adjacent substrates to form a
substantially continuous volume of translucent solidified sugar
with colored ink(s) contained within. In this example, the stack
can additionally or alternatively be heated and then cooled in
Block S180 to reflow and harden portions of the substrates into a
single continuous volume of material with ink trapped within, and
the stack can be compressed normal to a dominant face of a
substrate within the stack to displace pockets of air or other
gases from the stack and/or to yield more uniform growth of sugar
crystals within the stack.
[0055] Alternatively, substrates within the stack can be bound
together after the vacuum process (i.e., upon completion of Blocks
S170, S180, and S190) or in place of the vacuum process. In one
example, the stack is arranged in a (transparent) clamping fixture
that retains the substrates in position. In another example,
adjacent edges of the substrates (and filler panels) are melted
together, such as chemically, by heating the perimeter edges of the
substrates in the stack on a hot plate, or by passing a hot blade
or a hot wire through the stack across the substrates. In another
example, the stack is constraining a clear rigid box or a clear
soft bag, which can be further filled with index-matching fluid and
sealed. In yet another example, the entire stack can be heated and
compressed to melt the substrates (and filler panels) into a single
cohesive structure with ink trapped therein. In another example,
edges of the stack can be dipped into a molten material
substantially identical to the substrate material to seal and
retain the edge faces of the substrates in the stack.
[0056] However, the first method S100 can be implemented in any
other way to manufacture a physical volumetric representation of a
virtual three-dimensional object or scene.
2. Second Method: Printed Polymer Layers and Applications
[0057] As shown in FIG. 2, a method for manufacturing a physical
volumetric representation of a virtual three-dimensional object
includes: receiving a series of adjacent cross-sections of the
virtual three-dimensional object in Block S210, the series
including a first cross-section of the virtual three-dimensional
object and a second cross-section of the virtual three-dimensional
object; depositing a first layer of transparent polymer over a
build platform in Block S220; curing a portion of the first layer
of transparent polymer in Block S230; with ink, printing an image
of the first cross-section onto a cured exposed dominant face of
the first layer in Block S240; depositing a second layer of
transparent polymer over the first layer of transparent polymer in
Block S222; curing a portion of the second layer of transparent
polymer in Block S232; with ink, printing an image of the second
cross-section onto a cured exposed dominant face of the second
layer according to an order of the series of cross-sections in
Block S42; and releasing a stack of layers including the first
layer of transparent polymer and the second layer of transparent
polymer from the build platform in Block S250.
[0058] Generally, like the first method S100 described above, the
second method S200 can be implemented in manufacture of a
three-dimensional volumetric "print" exhibiting a three-dimensional
graphic representation of an object or multiple objects, such as a
scene, in physical space. However, the second method S200
interfaces with a first print head to deposit a transparent polymer
into a series of stacked layers and with a second print head (or
similar apparatus) to deposit ink onto each layer before a
subsequent layer is printed thereover. Therefore, rather than
printing on discrete substrates and arranging the discrete
substrates into a stack as in the first method S100, the second
method S200 can "print" a first substrate, print onto the first
substrate an image of a first cross-section of a virtual object to
be physically represented in a real model, print a second substrate
over the first substrate and the image of the first cross-section,
print onto the second substrate an image of a second cross-section
of the virtual object, and so on until the full thickness of the
virtual object to be represented physically in the completed real
model.
[0059] For example, the second method S200 can control a first
print head to deposit a sequence of planar UV-curable translucent
resin layers (i.e., substrates) of substantially uniform thickness,
such as successive resin layers 0.01 mm to 5 mm in thickness
desired resolution of the real model. The second method S200 can
also control a light source to cure each successive layer of resin
by exposing the layer to UV light for a particular period of time,
interface with a print head to deposit UV-curable ink in the form
of a cross-section of the virtual model on successive layer of
cured resin, and then again control the same or other light source
to cure the ink via exposure to UV light. Thus, the second method
S200 can print a successive resin and ink layers to generate a real
model that represents a virtual model in physical space.
2.1 Cross-Sections
[0060] Block S210 of the second method S200 recites receiving a
series of adjacent cross-sections of the virtual three-dimensional
object, the series including a first cross-section of the virtual
three-dimensional object and a second cross-section of the virtual
three-dimensional object. Generally, Block S210 functions like
Block S110 of the first method S100 to collect and/or generate a
series of cross-sections corresponding to a virtual model to be
represented in physical space by printing images of the cross
sections on a sequence of substrates (i.e., printed polymer layers)
in subsequent Blocks of the second method S200.
2.2 Printing Substrates
[0061] Block S220 of the second method S200 recites depositing a
first layer of transparent polymer over a build platform, and Block
S222 of the second method S200 recites depositing a second layer of
transparent polymer over the first layer of transparent polymer.
Generally, Blocks S220 and S222 functions to deposit a sequence of
layers of material, each of a particular depth and footprint over a
surface, such as the base of a build chamber within a
three-dimensional printer or a previous layer of the material. For
example, Block S220 can print a planar layer of photo-curable resin
0.3 mm in thickness, 80 mm in width, and 100 mm in length over a
previous layer of the same footprint and thickness. In this
example, Block S222 can then print another layer of the material on
top of the previous layer to create a rectilinear stack as in the
first method S100. Alternatively, Block S220 and Block S222 can
print layers of various differing thicknesses, such as based on
different resolution requirements at various depths within the
stack.
[0062] Block S220 and Block S222 can additionally or alternatively
print layers of differing footprints, such as to create the real
model that exhibits a physical geometry representative of the
virtual model. For example, Blocks S220 can print a first layer of
material with a footprint substantially identical to a first
cross-section of the virtual model generated in Block S110, Block
S230 can print the first cross-section onto the first layer, Block
S222 can print a second layer of material with a footprint
substantially identical to a second cross-section of the virtual
model--different from the first cross-section--generated in Block
S110, and Block S232 can print the second cross-section onto the
second layer, etc. such that the completed real model both contains
a visual representation of the virtual model in the form of ink
between layers and defines a three-dimensional physical
representation of the virtual model. Blocks S220 and S222 can
similarly trim corresponding layers of deposited polymer to various
footprints. For example, a laser cutter or mechanical knife
integrated into the 3D printer can execute Block S220 to trim
excess material from a corresponding layer of polymer, such as once
the layer is cured in Block S230, thereby yield a substantially
crisp, straight edge around a perimeter of the layer. In these
implementations, Blocks S220 and S22 can also print sacrificial
support structures to support overhanging regions of corresponding
layers, and the sacrificial support structures can be dissolved or
otherwise removed from the stack once deposition of the ink and
layers of polymer is complete.
[0063] Block S220 and Block S222 create the stack by depositing a
material that is substantially transparent or that is substantially
transparent when cured. For example, Block S220 can deposit a
transparent thermoform plastic, such as acrylic, by dispensing raw
material into a heated print head, heating the raw material above a
glass phase change temperature, dispensing the now-fluid material
from the print head onto a build platform or a previous layer of
material within a build chamber, and then allowing the deposited
layer to cool before dispensing a second layer or ink there over in
Block S222 or Block S230, respectively.
[0064] Alternatively, Block S220 can deposit light-activated resin
(e.g., UV-curable resin, photo-curable resin) over the build
platform or previous layer of material. For example, Blocks S220
and S222 can execute on a "3D printer" incorporating a controllable
light source and arranged within a dark room and thus control the
3D printer to deposit a sequence of layers of viscous photo-curable
resin that is substantially transparent once cured. In this
example, Block S230 can trigger the light source to expose the
layer(s) to UV light to cure the layer(s), such as after each layer
is deposited and before ink is applied, after a subset of layers
are deposited, or after the complete stack is printed. Furthermore,
in this example, the viscosity of the resin can be selected or set
such that a new layer of material flows over a previous layer of
material smoothly and controllably but substantially without
pockets of trapping air within the new layer of between the new and
previous layers. For example, Blocks S220 and S222 can interface
with the 3D printer to control a heater within the build chamber
and/or a heater within the print head according to a target print
temperature at which the resin exhibits preferred or target flow
characteristics (e.g., viscosity). However, Blocks S220 and S222
can cooperate in any other way to manufacture a sequence of
substantially transparent layers of the same or different footprint
and thickness and of any other suitable transparent or translucent
material.
[0065] Block S230 of the second method S200 recites curing a
portion of the first layer of transparent polymer, and Block S232
of the second method S200 recites curing a portion of the second
layer of transparent polymer. Generally, Blocks S230 and S232
function to set and/or cure respective layers of the polymer
material prior to deposition of ink thereonto. In one example,
Blocks S230 and S232 fully cure respective polymer layers prior to
deposition of ink thereonto, such as by overexposing layers of
UV-curable ink with light from an adjacent light source, and Block
S240 and S242 can thus print corresponding images of cross-sections
onto fully-cured polymer layers. Alternatively, Blocks S230 and
S232 can expose corresponding polymer layers to curing procedures
sufficient to set and/or cure only a portion of a thickness of each
layer. For example, Block S230 can cure only a film of a layer
across a dominant face of the layer--adjacent a print head--to less
than a full thickness of the layer, and Blocks S240 can print onto
a cured film of layer though material beneath the film may not be
fully cured. In this example, once deposition of all layers and ink
in the stack is complete, Blocks S230 and S232 can further expose
the stack to the curing process of cure any material within the
stack that remains uncured or `loose.` However, Blocks S230 and
S232 can additionally or alternatively cure material in layers of
the stack during deposition of the polymer into corresponding
layers and/or upon completion of deposition of polymer layers and
ink into the stack.
[0066] In an implementation in which the polymer is a photo-curable
polymer, Blocks S230 and S232 can interface with a light source to
expose the layers of polymer to light. For example, Blocks S230 and
S232 can interface with a light source coupled to a 3D printing
apparatus to expose each successive layer of the polymer to light
for a duration of time corresponding to a thickness of a layer once
the layer is fully deposited. Block S230 (and Block S232) can
further delay a time between deposition of the layer and exposure
of the layer to the curing process. For example, Block S230 can set
a delay time for the curing process based on a viscosity of the
polymer, a step-over distance of the print head during deposition
of the layer, a vibratory setting of a build platform supporting
the stack, and/or a particular vacuum drawn around a build chamber
containing the stack, etc. such that substantially all air (or
other gases) trapped within the fresh layer of material is
evacuated therefrom prior to curing the layer.
[0067] In another implementation in which the polymer is a
high-temperature-cure polymer, Blocks S230 and S232 can interface
with a heating element adjacent the stack to execute a heating
schedule to cure one or more layers of the polymer. For example,
Blocks S230 and S232 can interface with a heat lamp coupled to a
print head of 3D printing apparatus to radiate heat onto each
successive layer of polymer for a duration of time corresponding to
a thickness of a layer, an ambient air temperature, a temperature
of a preceding layer during deposition of the layer, etc. once the
layer is fully deposited from the print head onto a preceding layer
of polymer.
[0068] In yet another implementation in which the polymer is cured
by a chemical catalyst, Blocks S230 and S232 interface with a
nozzle and pump within the 3D printer to spray a catalyst onto a
layer of polymer to cure the layer. Similarly, the 3D printer can
mix the polymer material and the catalyst as the material is
dispensed out of the print head and onto a build platform or onto a
previous layer of the polymer. In this implementation, Blocks S240
and S242 further delay deposition of ink onto corresponding layers
based on an estimated cure status of the layers, such as based on a
model linking curing time to layer thickness, catalyst ratio,
etc.
[0069] In another implementation, Blocks S220 and S222 dispense a
sugar-based syrup, and Blocks S230 and S232 cure dispensed volumes
of the syrup into corresponding translucent layers prior to
dispensation of inks onto dominant faces of the layers in Block
S240 and S242. For example, Blocks S220, S222, S230, S232, S240,
and S242 can be executed by a three-dimensional printing machine
including a planar build platform that runs vertically inside a
bounded wall below a print head. In this example, the Block S220
sets a top surface of the build platform to a particular distance
below a top edge of the bounded wall and dispenses a first preset
volume of a heated sugar-based syrup (e.g., an isomalt syrup at
425.degree. F., or a mixture of white sugar and cream of tartar).
In this example, the three-dimensional printing machine then
hardens the first volume of syrup into a first transparent (or
translucent) layer of sugar--such as by (rapidly) cooling the build
platform and the bounding wall, by heating the boundary wall and
the build platform to evaporate moisture from the syrup, and/or by
drawing a partial vacuum around the first volume of syrup to
evaporate moisture therefrom--in Block S230 before printing a first
image of a corresponding cross-section onto the hardened layer in
Block S240. The three-dimensional printing machine can then execute
Block S222 by indexing the build platform downward away from the
print head by a distance approximating a thickness of the first
layer of hardened syrup and dispensing a second volume of the syrup
over the first layer and the first image, can execute Block S232 by
curing (e.g., hardening) the second layer as described above, and
can execute Block S242 by printing a second image of a
corresponding cross-section onto the hardened second layer.
Alternatively, in another example of this implementation, the
three-dimensional printing machine can include a heated print head
(e.g., nozzle) that heats moistened grains of sugar into syrup, and
the printing machine executes Blocks S220 and S222 by forcing sugar
through the heated print head and rastering the print head over the
build platform or a previous layer of hardened sugar to form each
subsequent layer. In this example, the three-dimensional printing
machine can execute Blocks S230 and S232 by cooling a deposited
layer of sugar (E.g., by blowing air across the layer) or by
waiting sufficient time for the layer to harden before executing
Blocks S240 and S242.
[0070] However, Blocks S220 and S222 can deposit sequential layers
of any other suitable type of material, and Blocks S230 and S232
can function in any other way to cure all or a portion of the
corresponding layers.
2.3 Printing Ink
[0071] Block S240 of the second method S200 recites, with ink,
printing an image of the first cross-section onto a cured exposed
dominant face of the first layer, and Block S242 of the second
method S200 recites, with ink, printing an image of the second
cross-section onto a cured exposed dominant face of the second
layer according to an order of the series of cross-sections.
Generally, Blocks S240 and S242 function like Block S140 of the
first method S100 described above to deposit colored inks (e.g.,
cyan, magenta, yellow, black, and/or white inks) onto a dominant
face of a corresponding layer of polymer recently printed (and
cured). In particular, Block S240 (and Block S242) can print a
two-dimensional representation of a corresponding (e.g., first)
cross-section onto a (cured) dominant face of a corresponding
(e.g., a first) layer.
[0072] In one implementation, Block S240 (and Block S242)
interfaces with a print head to deposit a combination of
light-activated cyan ink, light-activated magenta ink,
light-activated yellow ink, and light-activated black ink onto a
cured exposed dominant face of a corresponding layer of transparent
polymer. In this implementation, like Block S230, Block S240 can
further cure deposited ink by exposing the fresh ink to light. For
example, Blocks S230 and S240 can interface with the same light
source within the 3D printer to expose light-activated ink.
Alternatively, Block S240 can control a second light source within
or adjacent the 3D print to cure the fresh ink. However, Block S240
(and Block S242) can print any other type of ink of any other color
and can cure deposited ink in any other suitable way.
[0073] Blocks S220, S222, S230, S232, S240, and S242 can therefore
cooperate to control one or more printing apparatuses to deposit a
sequence of polymer layers with images of cross-sections of a
virtual model printed between polymer layers. For example, Blocks
can S220, S222, S230, S232, S240, and S242 be executed by a single
apparatus or manufacturing system incorporating a first print head
that dispenses a transparent polymer, a second print head that
dispenses a colored ink (e.g., one print head that dispenses
various colors of ink or multiple print heads that each dispense
one ink color), one or more material curing subsystems (e.g., one
or more light sources directed toward a building platform), a build
platform that supports deposited polymer layers, an X- and Y-axis
table that moves the print heads laterally and longitudinally
relative to the build platform, and a Z-axis actuator that moves
the print heads vertically relative to the build platform. However,
Blocks S220, S222, S230, S232, S240, and S242 can be executed on
any other one or more apparatus to print ink and polymer to
generate the real model that represents the virtual model in real
space.
2.4 Post Processing
[0074] Block S250 of the second method S200 recites releasing a
stack of layers including the first layer of transparent polymer
and the second layer of transparent polymer from the build
platform. Generally, Block S250 functions to release the stack upon
completion of deposition of ink and polymer layers for each
cross-section in the set of cross-sections of the virtual model.
For example, the stack can be broken off of a support structure on
a build platform within the 3D printer, pried off the build
platform, or released from a vacuum clamping system within the 3D
printer.
[0075] Once the stack is released, the stack can be post-processed.
In one implementation, external surfaces of the stack are smoothed
to reduce reflections and refraction of light at the surfaces of
the stack. For example, the stack can exhibit rough surfaces along
edges of the layers, and these faces of the stack can be placed on
a hot planar surface to melt these rough faces into substantially
planar faces that exhibit improved optical clarity. Alternatively,
these faces can be machined to planar, polished chemically, and/or
polished mechanically. Yet alternatively, the stack can be
machined, etched, laser cut or ablated, compression molded, melted,
or otherwise formed into an other three-dimensional (e.g., non
rectangular) form upon completion of the additive build cycle.
However, the stack can be processed in any other way in Block S250
following completion of the build cycle in Blocks S220, S222, S230,
S232, S240, and S242, etc.
2.5 Porous Layers and Applications
[0076] As shown in FIG. 9, one variation of the second method S200
further includes Block S260, which recites etching the exposed
dominant face of a layer to create pores in the exposed dominant
face of the layer. Generally, Block S260 functions to create pores
in a deposited layer of polymer prior to deposition of ink onto the
layer such that deposited into may bleed into the pores in the
layer, thereby increasing a depth of ink contained by the single
layer and increasing a viewing angle (relative to adjacent dominant
faces of layers within the assembled stack) of the real model at
which the physical representation of the virtual object is visible.
Block S260 can thus form pores across dominant faces of substrates
to improve 360.degree. visibility of the physical representation of
the virtual model within the stack. For example, Block S260 can
form pores in a substrate that are of depth less than a thickness
of the substrate, such as .about.50% of the thickness of the layer.
Alternatively, Block S260 can create pores that extend through a
full thickness of the layer to a layer below, thereby linking
images of cross-sections on dominant faces of adjacent layers.
Block S260 also form a substantially uniform array of pores across
all or a portion of a layer, such as 100 pores per square
centimeter across the dominant face of a layer, or a substantially
random pattern of substantially uniform or (widely) varying pore
density across all of a portion of a dominant face of a layer. For
example, Block S260 can create a high density of pores in a first
area of a dominant face of a layer to yield perception of a darker
shadow in the first area in the real model, and Block S260 can
create a lower density of pores in a second area of the dominant
face to mimic a lighter shadow in the second area in the real
model.
[0077] In one implementation, the second method executes on the 3D
printer that further includes a laser diode coupled to a laser
output optic mounted adjacent the print head(s), and the 3D printer
implements Block S260 by rastering a laser beam from the laser
output optic across the dominant face of a cured (or semi-cured)
first layer of polymer material to etch a substantially uniform
array of pores to a depth less than a thickness of the first layer
across the dominant face, as shown in FIG. 9. Block S240 can
subsequently deposit ink across the dominant face, and deposited
ink can wick into adjacent pores in the first layer to increase an
effective depth of visual information stored in (i.e., printed
onto) the first layer. In this implementation, Block S222 can print
a subsequent (i.e., second) layer of polymer material over the
first layer, and uncured polymer material can similarly wick into
pores not filled with ink prior to curing the second layer such
that the pores are not substantially visible in the completed real
model. Block S260 can therefore includes irradiating an exposed
dominant face of a layer with a laser beam to create an array of
pores in the first layer at a depth less than a thickness of the
first layer.
[0078] In a similar implementation, the 3D printer rasters the
laser beam from the laser output optic across an area of the layer
only over which an image of a cross-section will subsequently be
printed. In this implementation, Block S240 (and Block S242) can
further print ink volumes onto the dominant face of the
corresponding layer according to volume of open pores within an
area of the dominant face onto with a corresponding image of a
cross-section will b printed. Block S240 can therefore cooperate
with Block S260 to dispense sufficient ink onto a "porous" dominant
face of a layer to substantially ensure that all pores in the
dominant face will be filled with ink, thereby reducing likelihood
that air will be trapped in pores of one layer when polymer
material of a subsequent layer is dispensed thereover.
[0079] However, Block S260 can additionally or alternatively form
pores in the dominant face of a layer by stamping, drill, bulk
micromachining, mechanically cutting, or through any other suitable
process or technique. Block S260 can also create pores that are
cylindrical, elliptical or rectilinear in cross-section, or of any
other form or section.
[0080] The first method S100 can similarly print images of
cross-sections onto porous substrates. For example, Block S140 can
print images on substrates that are preformed with pores, such as
by injection molding, stamping vacuum forming, machining, etching,
laser ablating, casting, or otherwise forming pores into pre-form
sheets of transparent material. Alternatively, the first method
S100 can include stamp, cut, mold, or otherwise form an array of
pores in a substrate in situ just before or during deposition of
ink in the form of an image of a cross-section of the virtual model
onto a dominant face of the substrate. However, the first method
can print images of cross-sections of the virtual model onto
substrates of any of form and incorporating any other suitable
feature.
2.6 Magnets
[0081] In one variation, the second method S200 includes forming a
bore in a substrate in the set of substrate and installing a
magnetic element into the bore in the substrate assembled into the
stack. Generally, in this variation, the second method S200 can
incorporate an element into the stack such that the stack can
interface with (e.g., couple to) another stack via the magnetic
element. For example, Block S220 can deposit a rectangular first
layer of transparent material that defines a recess at each corner
and then print a slurry of epoxy and magnetic powder into each
recess, Block S230 can cure the slurry into magnetic inserts, and
Block S222 can deposit a second layer of transparent material over
the recess to enclose the cured slurry. Once manufacture of the
stack is completed, the cured magnetic inserts can attract the
stack to similar magnetic inserts in another stack. Alternatively,
Block S220 can deposit a layer of transparent material defining one
or more bores, and magnetic elements can be inserted into each bore
upon completion of a last layer of transparent material onto the
stack. Yet alternatively, bores can be drilled, etched, bulk
micro-machined, or otherwise formed into the stack, and magnetic
(or ferrous) elements can be pressed into, glued into, or otherwise
installed into the bores such that the stack interfaces with one or
more other stacks similarly including magnetic and/or ferrous
elements.
[0082] In this variation, the stack can contain a physical
representation of a first virtual model and can interface with a
second stack--via the magnetic inserts--containing a physical
representation of a second virtual. For example, the (first) stack
can include a physical representation of a human, a second stack
can include a physical representation of a tree, a third stack can
include a physical representation of a bird, a fourth stack can
include a physical representation of a grassy knoll, and a fifth
stack can include a physical representation of a sun, and each
stack in the set can include magnetic elements that transiently
retain the stacks against each other. In this example, a user can
rearrange the stacks, such as to move the physical representation
of the human from behind the physical representation of the tree to
in front of the tree, and the magnetic elements can retain the
assembly of five discrete stacks in a position thus set by the
user.
[0083] In this variation, the second method S200 can thus
incorporate one or more magnetic or ferrous elements into the stack
such that the stack may be transiently connected to one or more
other stacks similarly including magnetic or ferrous elements. For
example, for each cubic stack, the stack can include a magnetic
element in each of its corners for a total of eight magnetic
elements, proximal a center of each face for a total of six
magnetic elements, or near a center of each edge of each face of
the stack for a total of twenty-four magnetic elements. The
magnetic elements can also be installed directionally into the
stack. For example, north and south poles of each magnetic can be
phased in the stack according to pole scheme such the stack can
interface with (e.g., magnetically couple to) other stacks in a
limited number of controlled orientations. However, the second
method S200 can incorporate any other number of magnetic elements
in any other way into the stack.
[0084] The first method S100 can incorporate similar methods or
techniques to install one or more magnetic elements into the stack
such that the stack can interface with one or more stacks similarly
incorporating magnetic and/or ferrous elements.
3. Third Method: Cross-section Generation and Applications
[0085] As shown in FIG. 3, a third method S300 for manufacturing a
physical volumetric representation of a virtual three-dimensional
object includes: slicing the virtual three-dimensional object into
a set of virtual layers of discrete virtual thickness based on a
selected resolution for the physical volumetric representation in
Block S310; for each virtual layer in the set of virtual layers,
selecting a set of adjacent cross-sections of a portion of the
virtual three-dimensional object contained within the virtual layer
in Block S320; for each virtual layer in the set of virtual layers,
setting an opacity level for each cross-section in the set of
cross-sections in Block S330; for each virtual layer in the set of
virtual layers, combining the set of cross-sections into a
composite cross-section based on an opacity level set for each
cross-section in the set of cross-sections in Block S340; for each
virtual layer in the set of virtual layers, printing the composite
cross-section onto a transparent portion of a dominant face of a
substrate in a set of substrates in Block S350; and arranging the
set of substrates into a stack, each substrate in the set of
substrates positioned within the stack according to a position
within the virtual three-dimensional object of a cross-section
printed on the substrate in Block S360.
[0086] Generally, the third method S300 functions to combine
multiple adjacent cross-sections of the virtual model into a single
two-dimensional image that can be printed onto one dominant face of
a substrate (or polymer layer) within a set of substrates assembled
or printed into a stack as in the first method S100 and the second
method S200 described above. In particular, the third method S300
can generate composite cross-sections of a virtual model that yield
reduced contour effects when printed onto substrates of discrete
thickness and arranged in a stack as described above. For example,
Block S110 of the first method S100 or Block S210 of the second
method S200 can execute the third method S300 to slice a virtual
three-dimension model of an object into adjacent virtual layers of
constant discrete virtual thickness corresponding to a target
center-to-center distance between substrates in a corresponding
real model, select a number of cross-sections offset by some
virtual distance in each virtual layer, set an opacity for each
cross-section in each virtual layer, and combine cross-sections in
each virtual layer into a composite cross-section corresponding to
each virtual layer in the virtual model. The subsequent Blocks of
the first method S100 or the second method S200 can then print
images of the composite cross-sections onto substrates (i.e.,
polymer layers) to create a stack depicting a three-dimensional
representation of the image. In this example, the stack can include
101 substrates defining 100 planar interstices between adjacent
substrates on which images of the virtual model are printed.
However, the third method S300 can capture 10,000 cross-sections
equally spaced through the virtual model and combine sets of 100
adjacent cross-sections into single composite cross-sections, and
images of the cross-sections can then be printed on dominant faces
of the substrates such that the complete stack depicts 100 images
of composite cross-sections representing 10,000 cross-sections of
the virtual object, thereby reducing perceived steps between layers
in the stack and increasing perceived resolution of the real model
over a real model with 100 images representing only 100
cross-sections of the virtual model.
[0087] The third method S300 can therefore be executed on a
computer device, such as within a three-dimensional printing
application or software, a CAD program, etc. on a desktop or laptop
computer. Alternatively, the third method S300 can be executed by a
3D printer implemented the first method S100 and/or the second
method S200 described above. However, the third method S300 can be
implemented on any other device and in any other way.
3.1 Virtual Layers
[0088] Block S310 of the third method S300 recites slicing the
virtual three-dimensional object into a set of virtual layers of
discrete virtual thickness based on a selected resolution for the
physical volumetric representation. Generally, Block S310 functions
to define a set of virtual (planar) layers of defined virtual
thickness within the virtual model.
[0089] In one implementation, Block S310 receives a selection for a
scale of the real model, such as a scale relative to the virtual
model, a maximum real dimension of the real model, or a real
dimension of a feature of the real model through a user interface,
as shown in FIG. 6, and Block S310 then scales the virtual
three-dimensional object according to the scale selection. In this
implementation Block S310 further receives a resolution selection
for the real model, such as a maximum real or perceived distance
between substrates in the completed stack, sets a target
center-to-center distance between substrates within the real stack
based on the resolution selection and the scale selection, and then
slices the scaled virtual three-dimensional object into the set of
virtual layers of virtual thickness approximating the target
center-to-center distance. For example, for a virtual sphere, Block
S310 can receive a scale selection for representation of a 100
mm-diameter sphere in the real model, receive a resolution
selection of 0.05 mm, select a default substrate thickness of 0.5
mm (e.g., based on available materials or resolution capabilities
of the 3D printer), and slice the virtual model of the sphere into
200 layers, each corresponding to a thickness of 0.5 mm in the real
mode, based on the scale selection. However, because the resolution
requirement is smaller than the target center-to-center distance
between adjacent substrates, Block S310 can trigger Block S320 to
select at least ten cross-sections per virtual layer such that a
cross-section of the virtual model corresponding to at least every
0.05 mm in the real model is recorded in Block S320 in order to
satisfy the resolution selection of 0.05 mm. Block S310 can
therefore "slice" the virtual model into a set of virtual layers
based on a scale (e.g., size) selection of the real model.
[0090] Alternatively, Block S310 can slice the virtual
three-dimensional object into a preset or default number of virtual
layers, each corresponding to a thickness in the real model, and
thus select or calculate a per-substrate thickness for the real
model accordingly. However, Block S310 can define a virtual layer
of discrete virtual thickness within the virtual model in any other
suitable way and according to any other suitable schema.
3.2 Micro-Slices
[0091] Block S320 of the third method S300 recites, for each
virtual layer in the set of virtual layers, selecting a set of
adjacent cross-sections of a portion of the virtual
three-dimensional object contained within the virtual layer.
Generally, Block S320 functions to select a set of discrete
two-dimensional cross-sections of the virtual model contained
within each virtual layer of the virtual model selected in Block
S310. For example, Block S320 can select adjacent and parallel
two-dimensional cross-sections of the virtual model set at uniform
virtual offset distances throughout the virtual model. In this
example, Block S320 can select--for each virtual layer in the set
of virtual layers defined in Block S310--a first cross-section, a
second cross-section, and a third cross-section within the virtual
layer, wherein the second cross-section is interposed between the
first cross-section and the third cross-section such that more
cross-sections are selected from the virtual model than a number of
substrates allocated for the real model.
[0092] In the example above in which Block S320 sets a
center-to-center distance for adjacent substrates at 0.5 mm and
receives a resolution selection of 0.05 mm, Block S320 can select
at least ten parallel cross-sections offset by a constant distance
from each virtual layer of the virtual model defined in Block S310.
For example, Block S320 can select, from each virtual layer, ten
cross-sections spaced apart by a virtual distance corresponding to
0.05 mm in real space, including one cross-section at each of a
virtual thickness of a virtual layer corresponding to 0.00 mm, 0.05
mm, 0.10 mm, 0.15 mm, 0.20 mm, 0.25 mm, 0.30 mm, 0.35 mm, 0.40 mm,
and 0.45 mm in the real model.
[0093] Alternatively, Block S320 can select a preset number or at
least a minimum number of cross-sections from each adjacent virtual
planar rectilinear layer defined in the virtual model. Block S320
can also vary a number of cross-sections selected per virtual
layer. For example, Block S320 can qualify a level of detail in the
virtual model for each virtual layer and set a number of
cross-sections per layer accordingly, such as by setting a higher
number of selected cross-sections per virtual layer for a virtual
layer exhibiting a higher level of details than for a virtual layer
exhibiting a lower level of detail.
[0094] However, Block S320 can select any one or more
cross-sections of the virtual model from each virtual layer in any
other suitable way and according to any other schema.
3.3 Opacity
[0095] Block S330 of the third method S300 recites, for each
virtual layer in the set of virtual layers, setting an opacity
level for each cross-section in the set of cross-sections.
Generally, Block S330 functions to define a parameter for combining
cross-sections within each virtual layer into composite
cross-sections by setting opacity levels (i.e., a degree of
translucency) for each cross-section of the virtual model selected
in Block S320. In particular, Block S330 can set opacity levels for
each cross-section selected from a virtual layer in Block 320 such
that, when aggregated into a single composite cross-section,
distinct features of each cross-section (e.g., geometry, color,
shading, line weight, etc.) in a virtual layer are represented and
visible within the composite cross-section at least to some degree,
as shown in FIGS. 5A, 5B, 5C, and 5D.
[0096] In one implementation in which Block S320 selects a preset
or default number of cross-sections from each virtual layer, Block
S330 applies a static opacity level schedule to the cross-sections
in the virtual layer. For example, Block S320 can select a first
cross-section, a second cross-section, and a third cross-section
within the virtual layer, wherein the second cross-section is
interposed between the first cross-section and the third
cross-section, and Block S330 can set a first opacity of the first
cross-section at 40%, a second opacity of the second cross-section
at 30%, and setting a third opacity of the third cross-section at
60% according to an opacity schedule specifying [0.40, 0.30, and
0.60]. Alternatively, Block S330 can set the opacity levels for all
cross-sections in a virtual layer as equivalent, such as by setting
opacity levels for each cross-sections in a later to 39%.
[0097] Alternatively, Block S330 can implement an algorithm, model,
or step function to calculate opacity levels for cross-sections
within a virtual layer based on a number of selected cross-sections
within the virtual layer. For example, Block S320 can select thirty
cross-sections per virtual layer, and Block S330 can set an
increasing opacity from 1% to 100% for cross-sections 1 through 10
and a decreasing opacity from 100% to 1% cross-sections 11 through
30 such that opacity control within a virtual layer scales with the
virtual width of a virtual "slice" (i.e., a virtual layer) of the
virtual model, thereby reducing a contour effect within the real
model without artificially increasing contrast in certain regions
of the volumetric image within the real model. However, Block S330
can set opacity (i.e., transparency) levels of cross-sections of
the virtual model in nay other way and according to any other
schema.
3.4 Composite Cross-Sections
[0098] Block S340 of the third method S300 recites, for each
virtual layer in the set of virtual layers, combining the set of
cross-sections into a composite cross-section based on an opacity
level set for each cross-section in the set of cross-sections.
Generally, Block S340 functions to aggregate the cross-sections of
each virtual layer into a single composite cross-section
corresponding to each virtual layer according to opacity levels set
of the cross-sections in each virtual layer.
[0099] In one implementation, Block 340 adjusts opacity levels for
each cross-section in a virtual layer and then virtually overlays
the cross-sections (in the virtual layer) over each other and in
order to virtually (i.e., digitally) create the composite
cross-section. Thus, in areas of adjacent cross-sections that are
the same color, texture, cross hatch, etc., the corresponding area
of the composite cross-section may appear darker and/or sharper
than for an area of the composite cross-section corresponding to an
area of color, texture, cross hatch, etc. of a cross-section that
is unique to the set of cross-sections within the virtual layer.
Block S350 can then implement any of the techniques or methods
described above to print an image of a composite cross-section onto
a dominant face of a corresponding substrate of the stack.
[0100] In another implementation, Block S340 groups cross-sections
of a virtual layer into subsets and aggregates cross-sections in
subsets into composite cross-sections. For example, Block S320 can
select thirty cross-sections within a virtual layer, and Block S340
can combine--as in the foregoing implementation--cross-sections 1
through 15 into a first composite cross-section according to
opacity levels assigned to cross-sections 1 through 15 in Block
S330, and Block S340 can combine cross-sections 16 through 30 into
a second composite cross-section according to opacity levels
assigned to cross-sections 16 through 30 in Block S330. Block S350
can then implement any of the foregoing methods or techniques to
print an image of the first composite cross-section onto a dominant
face of a corresponding substrate and to then print an image of the
second composite cross-section over the first composite
cross-section on the same dominant face of the substrate.
Alternatively, Block S350 can implement the foregoing methods or
techniques to print an image of the first composite cross-section
onto a first dominant face of a corresponding substrate and to then
print a mirrored image of the second composite cross-section over a
second dominant face of the substrate opposite the first dominant
face.
[0101] However, in another implementation, Block S350 prints images
of all (or a subset) of single cross-sections in a virtual
layer--one top of the preceding and in order --onto one dominant
face of a corresponding substrate. Block S350 can thus print
multiple images of composite or single cross-sections of a virtual
layer onto one or more dominant faces of a corresponding
substrate.
3.5 Blurring
[0102] In one variation, Block S340 blurs or "feathers" a periphery
or (or enclosed area within) a singular cross-section or a
composite cross-section to generate an adjusted cross-section that,
when printed onto a substrate in an assembled stack, yields reduced
contour effects around a represented surface of the virtual model
within the stack. Block S350 can then print a single (i.e., not
composite) cross-section of the virtual model within blurred
periphery onto each substrate in the set of substrates in the
stack, or Block S350 can then print a composite cross-section of
the virtual model within blurred periphery onto each substrate in
the set of substrates in the stack. However, Block S340 can
function in any other way to blur or feather a portion of singular
cross-section or a composite cross-section to reduce a perceived
contour effect (e.g., perceived topographical-like contour lines)
within the real model.
3.6 Printing Cross-Sections and Assembly
[0103] Block S350 of the third method S300 recites, for each
virtual layer in the set of virtual layers, printing the composite
cross-section onto a transparent portion of a dominant face of a
substrate in a set of substrates, and Block S360 of the third
method S300 recites assembling the set of substrates into a stack,
each substrate in the set of substrates positioned within the stack
according to a position within the virtual three-dimensional object
of a cross-section printed on the substrate. Generally, Blocks S350
and S360 can implement any of the methods or techniques of the
first method S100 or the second method S200 to print images of
(singular or) composite cross-sections of each virtual layer in the
virtual model onto dominant faces of corresponding substrates and
to complete the real model. For example, as in the second method
S200 described above, Block S350 and Block S360 can include
printing a new layer of transparent polymer onto a previous layer
of transparent polymer, curing a portion of the new layer of
transparent polymer into a substrate, and, with ink, printing a
composite cross-section onto an exposed dominant face of the new
layer of transparent polymer for each virtual layer in the set of
virtual layers.
[0104] As described above, Block S350 can also print on both
dominant faces of a substrate, such as to improve resolution of the
real model without increasing a number of substrates in the stack.
However, Block S350 and Block S360 can implement any other methods
or techniques to print images of cross-sections of the virtual
model onto substrates in the sack and to complete the real
model.
4. Fourth Method: White Layer
[0105] A fourth method S400 for manufacturing a physical volumetric
representation of a virtual three-dimensional object includes:
selecting a series of cross-sections of the virtual
three-dimensional object in Block S410, for each cross-section in
the series of cross-sections, extracting a virtual color layer from
the cross-section in Block S420; for each cross-section in the
series of cross-sections, setting an opacity level of the virtual
color layer of the cross-section in Block S430; for each
cross-section in the series of cross-sections, extracting a virtual
white layer from the cross-section in Block S422; for each
cross-section in the series of cross-sections, setting an opacity
level of the virtual white layer of the cross-section in Block
S432; for each cross-section in the series of cross-sections,
applying a discrete image of the virtual color layer of the
cross-section onto a transparent portion of a corresponding
substrate in a set of substrates according to the opacity level of
the virtual color layer of the cross-section in Block S450; and
applying a discrete image of the virtual white layer of the
cross-section onto the transparent portion of the corresponding
substrate according to the opacity level of the virtual white layer
of the cross-section in Block S452; and arranging the set of
substrates into a stack in Block S460.
[0106] Generally, the fourth method S400 can be implemented in
conjunction with any other the foregoing methods to generate
virtual layers of cross-sections of a virtual model that, when
printed onto transparent substrates as described above, provide
advanced brightness and opacity control for a physical
representation of the virtual model contained within a stack of the
transparent substrates. In particular, the fourth method S400
generates discrete one or more virtual color (e.g., CMYK) images
and a discrete virtual white image of a cross-section of the
virtual model (or a composite cross-section of a virtual layer of
the virtual model), and the color and white images for a
cross-section of the virtual model can be printed separately and
adjacent--at corresponding opacity levels--onto a corresponding
substrate within the stack of substrates to form the real
model.
4.1 Cross-Sections
[0107] Block S410 of the fourth method S400 recites selecting a
series of cross-sections of the virtual three-dimensional object.
Generally, Block S410 can implement methods or techniques of Block
S110 of the first method S100, Block S210 of the second method
S200, and/or the third method S300 to select multiple
cross-sections of the virtual model.
[0108] In one example, a computing device executes Block S410 to
slice the virtual three-dimensional object into a set of virtual
layers of discrete virtual thickness based on a selected resolution
for the physical volumetric representation and to select a set of
adjacent secondary cross-sections of a portion of the virtual
three-dimensional object contained within the virtual layer for
each virtual layer in the set of virtual layers. Through Block
S410, the computing device can then set an opacity level for each
secondary cross-section in the series of secondary cross-sections
and combine the series of secondary cross-sections into a composite
cross-section based on an opacity level set for each secondary
cross-section in the series of secondary cross-sections for each
virtual layer in the set of virtual layers. Block S410 can thus be
implemented to generate a series of composite cross-sections, such
as described above.
[0109] In another implementation, Block S410 selects discrete
cross-sections at a constant offset through the virtual model, as
described above. However, Block S410 can function in any other way
to select a series of discrete or composite cross-sections of the
virtual model and to pass these cross-sections to Block S420.
4.2 White and Color Layers
[0110] Block S420 of the fourth method S400 recites, for each
cross-section in the series of cross-sections, extracting a virtual
color layer from the cross-section, and Block S422 of the fourth
method S400 recites, for each cross-section in the series of
cross-sections, extracting a virtual white layer from the
cross-section. Generally, Block S420 and Block S422 cooperate to
extract and/or separate and/or generate a color component and a
white component of each (discrete or composite) cross-section
selected in Block S410.
[0111] In one implementation, for each cross-section of the virtual
model, Block S422 converts the cross-section to a grayscale image,
inverts colors of the grayscale image to generate an inverted
grayscale image, maps each pixel in the inverted image into the
virtual white image according to an intensity value of each pixel
(or cluster of pixels) in the inverted grayscale image. Block S422
can thus generate a white layer--for a particular
cross-section--that exhibits varying intensities of white across a
virtual two-dimensional plane represented by the white layer, Block
S432 can set a global opacity adjustment across the whole white
layer, and Block S452 can print the white layer onto a
corresponding substrate according to the global opacity level by
printing dots of white ink at varying densities (e.g., varying dots
per inch) or in varying intensities (e.g., volumes of ink per dot),
etc. to replicate the varying intensities of white pixels defined
across the white layer.
[0112] In the foregoing implementation, Block S420 can thus convert
each cross-section in the set of (discrete or composite)
cross-sections into a cyan, magenta, yellow, and black pixel color
map. However, Blocks S420 and S422 can extract color and white
layers.
[0113] In one variation, Block S410 generates three composite
cross-sections per virtual layer of the virtual model, as in the
third method S300 described above. In particular, for each virtual
layer of the virtual model, Block S410 can generate a first
composite cross-section from (secondary) cross-sections within a
first half of a thickness of a virtual layer, generate a second
composite cross-section from (secondary) cross-sections within a
second half of the thickness of the virtual layer, and generate a
third composite cross-section from (secondary) cross-sections from
both the first and second halves of the virtual layer. Block S420
can then extract a first virtual color layer from the first
composite cross-section and a second virtual color layer from the
second composite cross-section, and Block S422 can extra a virtual
white layer from the third composite cross-section for each virtual
layer of the virtual model. In this variation, Block S450 can print
an image of the first virtual color layer onto a corresponding
substrate, Block S452 can print an image of the virtual white layer
over the image of the first virtual color layer, and Block S450 can
print an image of the second virtual color layer over the image of
the white layer for each virtual layer in the virtual model.
4.3 Opacity
[0114] Block S430 of the fourth method S400 recites, for each
cross-section in the series of cross-sections, setting an opacity
level of the virtual color layer of the cross-section, and Block
S432 of the fourth method S400 recites, for each cross-section in
the series of cross-sections, setting an opacity level of the
virtual white layer of the cross-section. Generally, Blocks S430
and S432 function to set opacity levels for the virtual color layer
and the virtual white layer, respectively, such as by implementing
methods or techniques of Block S330 described above.
4.4 Printing
[0115] Block S450 of the fourth method S400 recites, for each
cross-section in the series of cross-sections, applying a discrete
image of the virtual color layer of the cross-section onto a
transparent portion of a corresponding substrate in a set of
substrates according to the opacity level of the virtual color
layer of the cross-section, Block S452 of the fourth method S400
recites, for each cross-section in the series of cross-sections,
applying a discrete image of the virtual white layer of the
cross-section onto the transparent portion of the corresponding
substrate according to the opacity level of the virtual white layer
of the cross-section, and Block S460 of the fourth method S400
recites, arranging the set of substrates into a stack. Generally,
Blocks S450, S452, and S460 function to implement methods or
techniques of the first method S100 and/or the second method S200
described above to apply colored ink (e.g., cyan ink, magenta ink,
yellow ink, and black ink) and white ink in the form of an image of
a virtual color layer(s) and in the form of an image of a virtual
white layer, respectively, onto a corresponding substrates and to
arrange (e.g., assemble, print) the substrates into a stack.
However, Blocks S450, S452, and S460 can function in any other way
generate the real model from white ink, colored ink, and a
transparent polymer material.
4.5 Digital Display
[0116] The methods and techniques of the fourth method S400 (and
other methods described above) can similarly be implemented to
generate a transient representation of a virtual model within a
digital three-dimensional display, such as a stack of transparent
digital displays, wherein each discrete digital displays in the
three-dimensional display renders an image of a corresponding
cross-section of the virtual model. For example, the three
dimensional display can implement any of the foregoing methods or
techniques to generate virtual color and/or white layer of each
three-dimension virtual frame of a digital three-dimensional film,
and the stack of transparent displays can render correspond images
of the color and/or white layers at a present refresh rate (e.g.,
twenty frames per second).
[0117] The systems and methods of the preferred embodiment can be
embodied and/or implemented at least in part as a machine
configured to receive a computer-readable medium storing
computer-readable instructions. The instructions are preferably
executed by computer-executable components preferably integrated
with the application, applet, host, server, network, website,
communication service, communication interface,
hardware/firmware/software elements of a user computer or mobile
device, wristband, smartphone, or any suitable combination thereof.
Other systems and methods of the preferred embodiment can be
embodied and/or implemented at least in part as a machine
configured to receive a computer-readable medium storing
computer-readable instructions. The instructions are preferably
executed by computer-executable components preferably integrated by
computer-executable components preferably integrated with
apparatuses and networks of the type described above. The
computer-readable medium can be stored on any suitable computer
readable media such as RAMs, ROMs, flash memory, EEPROMs, optical
devices (CD or DVD), hard drives, floppy drives, or any suitable
device. The computer-executable component is preferably a processor
but any suitable dedicated hardware device can (alternatively or
additionally) execute the instructions.
[0118] As a person skilled in the art will recognize from the
previous detailed description and from the figures and claims,
modifications and changes can be made to the preferred embodiments
of the invention without departing from the scope of this invention
as defined in the following claims.
* * * * *