Systems and methods for construction of space-truss structures

Abstract

Systems and methods for construction of space-truss structures are described herein. In some embodiments, software is provided that includes a design module for providing a three-dimensional surface model for the space-truss structure and a fabrication module for providing construction specifications for the space-truss structure. The fabrication module can receive the three-dimensional surface model generated by the design module as input. The space-truss structure is constructed of components including nodes, rods, and panels. These components are generated using the construction specifications provided by the fabrication module. The nodes can include multiple node portions constructed of flat, metal plates having end portions that are bent at 90-degree angles with respect to a base portion for assembly.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit under 35 U.S.C. .sctn. 119(e) of U.S. patent application No. 60/629,787, filed Nov. 19, 2004, which is hereby incorporated by reference herein in its entirety.

TECHNICAL FIELD

[0002] The present invention relates to systems and methods for construction of space-truss structures, and more particularly to systems and methods for the design and fabrication of space-truss structures.

BACKGROUND

[0003] A space-truss is an efficient structural system employing bi-directional, offset lattices of rods and connecting nodes. Space-truss structures are typically built using a catalog of standard rods and nodes, leading to architecture of regular geometric forms, as in the geodetic domes of Buckminster Fuller and I. M. Pei's Javits Convention Center in New York.

[0004] When the rod lengths and node angles are varied across the structure, however, in what may be referred to as a "differential" space-truss, a diverse formal range of complex doubly curved structures can be realized. Despite their formal potential and structural efficiency, differential space-truss structures have not become prevalent in architecture primarily due to constraints of design, analysis, and fabrication.

SUMMARY

[0005] Systems and methods for construction of space-truss structures are provided.

[0006] In some embodiments of the present invention, a set of software components is provided that includes tools for designing space-truss structures and provides for the automatic generation of a parts inventory and digital files for fabrication and assembly of the structure. In conjunction with the software, a space-truss construction system is provided that can be easily and efficiently fabricated and assembled. The components of the space-truss construction system include a folded gusset-plate for structural connections. Thus, the construction system may be referred to as "Trusset," derived from the terms "truss" and "gusset."

[0007] While the space-truss construction system of the present invention has a diverse formal range at the global scale, it has specific formal limits at the scale of the individual rods and nodes. To address these formal limits and rules at a local scale, and to allow for design control at the scale of the overall structure, agent-based software is provided for the design and fabrication of the construction system. The software uses a collection of "intelligent" agents, each having a behavior controlled by an embedded logic embodying one or both of formal and construction limitations of the structural system.

[0008] The space-truss construction system and corresponding software design and fabrication tools provide a seamless pipeline from design to fabrication to assembly of a space-truss structure. The construction system is a clad differential space-truss designed for fabrication with computer numerically controlled ("CNC") linear cutting devices such as, for example, CNC laser cutters, two-axis mills, or water-jet cutting devices. The software component includes a set of agent-based design tools for developing surfaces and envelopes formally suitable to be built using the space-truss construction system of the present invention.

[0009] In some embodiments of the present invention, a method for designing and fabricating space-truss structures is provided. A three-dimensional surface model for a space-truss structure can be provided. Based at least in part on the three-dimensional surface model, construction specifications for the space-truss structure can be generated.

[0010] In one example, providing the three-dimensional surface model for the space-truss structure can include generating the three-dimensional surface model for the space-truss structure. The three-dimensional surface model for the space-truss structure can be generated by modifying the behavior of at least two agents. In one example, the behavior of the at least two agents can be modified by providing parameters for spacing between the at least two agents. In another example, the behavior of the at least two agents can be modified by applying an angle restriction to the at least two agents. In yet another example, the behavior of the at least two agents can be modified by identifying an area of attraction for the at least two agents. In still another example, the behavior of the at least two agents can be modified by identifying a rectilinear volume of space for the at least two agents to avoid. In yet another example, the behavior of the at least two agents can be modified by identifying an area through which the at least two agents produce a flat surface.

[0011] A space-truss geometry having a primary surface and an offset surface can be generated, for example, based at least in part on the three-dimensional surface model. In one example, polygons can be extracted from the primary and offset surfaces to generate the construction specifications. In another example, connection elements between the primary and offset surfaces can be extracted to generate the construction specifications. In yet another example, a node location can be extracted from the primary and offset surfaces to generate the construction specifications. The construction specifications can include, for example, instructions for a cutting device or a schedule of lengths for rod elements of the space-truss structure.

[0012] In some embodiments of the present invention, a device for designing and fabricating space-truss structures is provided. The device can include a processor executing an application. The application can be configured to provide a three-dimensional surface model for a space-truss structure and, based at least in part on the three-dimensional surface model, generate construction specifications for the space-truss structure.

[0013] In some embodiments of the present invention, a system for designing and fabricating space-truss structures is provided. The system can include means for providing a three-dimensional surface model for a space-truss structure and means for generating construction specifications for the space-truss structure. The construction specifications can be based at least in part on the three-dimensional surface model.

[0014] In some embodiments of the present invention, a computer readable medium storing computer executable instructions for designing and fabricating space-truss structures is provided. The executable instructions can include providing a three-dimensional surface model for a space-truss structure and generating construction specifications for the space-truss structure. The construction specifications can be based at least in part on the three-dimensional surface model.

[0015] In some embodiments of the present invention, construction specifications for a space-truss structure are provided. The construction specifications can be generated by a method that includes providing a three-dimensional surface model for a space-truss structure and, based at least in part on the three-dimensional surface model, generating the construction specifications for the space-truss structure.

[0016] In some embodiments of the present invention, a system for construction of a space-truss structure is provided. The system can include a node, a rod, a panel, and construction specifications for the node, rod, and panel. The construction specifications can be generated by providing a three-dimensional surface model for the space-truss structure and generating the construction specifications based at least in part on the three-dimensional surface model.

[0017] In some embodiments, a node for a space-truss structure is provided. The node can include an upper portion having a plurality of plates and a lower portion having a plurality of plates. Each plate can include a base portion and two end portions folded at about 90-degrees with respect to the base portion. Each end portion of each plate can be aligned with an end portion of another plate. The base portion of each plate of the upper portion can be positioned adjacent to the base portion of a plate of the lower portion.

[0018] The upper and lower portions can, for example, each include four plates. Each plate can, for example, have a notation indicating an assembly configuration for the plate. Each plate can, for example, have a marking positioned between an end portion and the base portion indicating a location for folding the plate at about 90-degrees.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other objects and advantages of the present invention will be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout, and in which:

[0020] FIG. 1 is a schematic diagram illustrating the behavior of agents controlled by a cellular automaton system in accordance with the present invention;

[0021] FIG. 2 is a schematic diagram illustrating the behavior of the agents of FIG. 1 modified by a flocking rule and angle limits within the modeling environment of the design module and in accordance with the present invention;

[0022] FIG. 3 is a schematic diagram illustrating the behavior of the agents of FIG. 2 further modified by attractors within the modeling environment of the design module and in accordance with the present invention;

[0023] FIG. 4 is a schematic diagram illustrating the behavior of the agents of FIG. 3 still further modified by an avoidance element within the modeling environment of the design module and in accordance with the present invention;

[0024] FIG. 5 is a schematic diagram illustrating the behavior of the agents of FIG. 4 still further modified by a combination of internal and external controls within the modeling environment of the design module and in accordance with the present invention;

[0025] FIG. 6 is a schematic diagram illustrating a space-truss structure generated from the behavior of the agents shown in FIG. 5 by the fabrication module in accordance with the present invention;

[0026] FIG. 7 is a schematic diagram illustrating a space-truss structure with square on square offset geometry in accordance with the present invention;

[0027] FIG. 8 is a schematic diagram further illustrating the offset geometry of the space-truss structure in accordance with the present invention;

[0028] FIG. 9 is an exploded perspective view illustrating an assembly of components for a space-truss structure in accordance with the present invention;

[0029] FIG. 10A is an elevational view illustrating a node assembly of a space-truss structure in accordance with the present invention;

[0030] FIG. 10B is a side sectional view taken through line A-A of FIG. 10A;

[0031] FIG. 11A is a sectional view illustrating the node assembly of FIG. 10A in accordance with the present invention;

[0032] FIG. 11B is a side sectional view taken through line B-B of FIG. 11A;

[0033] FIG. 12A is a sectional view illustrating dimensioning and performance criteria for an assembly of a rod and panel of an upper chord configuration of a space-truss structure in accordance with the present invention;

[0034] FIG. 12B is an elevational view of the upper chord configuration of FIG. 12A, and taken through line C-C of FIG. 12C, in accordance with the present invention;

[0035] FIG. 12C is a sectional view of the assembly of FIG. 12A and further illustrating a node portion of the space-truss structure in accordance with the present invention;

[0036] FIG. 12D is a sectional view further illustrating dimensioning and performance criteria for the rod of the space-truss structure in accordance with the present invention;

[0037] FIG. 13 is an illustrative flow diagram demonstrating the interaction of the design and fabrication modules in accordance with the present invention;

[0038] FIG. 14 is an illustrative flow diagram demonstrating the generation of a three-dimensional surface model by the design module in accordance with the present invention;

[0039] FIG. 15 is an illustrative flow diagram demonstrating the generation of a completed space-truss geometry by the fabrication module in accordance with the present invention; and

[0040] FIG. 16 is an illustrative flow diagram demonstrating the generation of space-truss component parameters by the fabrication module in accordance with the present invention.

Detailed Description

[0041] Systems and methods for construction of space-truss structures are provided.

[0042] In some embodiments of the present invention, software is provided that includes a design module and a fabrication module. The design module operates at the design level, assisting an architect in creating surfaces that are buildable using the space-truss construction system of the present invention. The design module uses a plurality of agents, and modifies the behavior of the agents using internal and external controls. The agents, as modified, form a three-dimensional surface model of a space-truss structure.

[0043] The fabrication module generates the completed space-truss geometry, and provides construction specifications for the structural components. The fabrication module receives as input, for example, a three-dimensional surface model or boundary edges of a space-truss structure. In one example, the surface is provided by the design module and received as input in the fabrication module. Alternatively, the surface model can be provided using any other suitable modeling method. A user can manually adjust the surface or boundaries to achieve a structurally feasible model. The fabrication module generates a completed space-truss geometry, based at least in part on the input surface model or boundary edges.

[0044] The fabrication module provides the construction specifications for the structural components of the system, such as the rods, nodes, and panels. (It should be noted that the terms "rods" and "struts" are used interchangeably herein.) The fabrication module extracts, for example, polygons, connection elements, and angle measurements from the completed space-truss geometry. The fabrication module provides as output construction specifications for the space-truss structure, including code for fabricating components of the structure and a schedule of lengths for various struts used in construction.

[0045] The code and schedule provided by the fabrication module can be used by CNC cutting devices to fabricate the components of the space-truss structure. The components of the structure can include, for example, panels, struts, and nodes. The nodes of the present invention can be constructed of, for example, sheet metal (e.g., steel) such that the nodes can be folded at a construction site for assembly.

[0046] The software of the present invention can be provided in any suitable programming language. For example, the software can be provided using C++, Alias|Wavefront's Maya.RTM. (Maya Embedded Language), Maxon's Cinema4d (COFFEE), or any other suitable language.

[0047] The design module of the software provides a simple interface for making forms that are buildable within the construction and fabrication limitations of the space-truss system. To provide a high-level design tool to architects and designers, the logic of the formal limitations of the building system is internalized into the software tool. These formal limitations are internalized in the software in the behavior of interdependent "intelligent" agents. The design module uses the constraints of the building system itself as behavioral constraints on coordinated autonomous agents. The intelligence of the agents is implemented as a layered logic. Along with the behavioral constraints of the construction logic, the agents have additional capabilities to react to internal and external control structures, thereby providing design control over the system.

[0048] The behavior of the agents can be controlled, for example, by a three-rule cellular automaton ("CA"). The logic of the CA system provides a communication mechanism between agents to produce a 3D patterning of the surface generated by the software. The discreet composition of cellular automata at a local scale provides a suitable analog to the organizational logic of the space-truss, which is also composed of discreet elements at the local scale. CA systems operate in a regular spatial matrix, the organization of the data offering an easy representation in a regular voxel array. In architectural applications of CAs, this has often led to regular geometric compositions. The software system of the present invention disconnects the data-structure of the CA system (rows of "cells") from its formal expression, using the CA states as instructions for the movement of the agents. FIG. 1 is a schematic diagram illustrating the behavior of agents 10 controlled only by a cellular automaton system in the software design module.

[0049] Layered on top of the behavior produced through the CA, the software employs operating rules to limit the behavior of the agents to a range of buildable relationships at a local scale. The construction system, described in additional detail hereinbelow, includes a plurality of rods and nodes. For fabrication and structural reasons, the rods may have a limited range of possible lengths between, for example, 100 cm and 150 cm. The software is programmed with a simple flocking rule that instructs the agents to maintain a minimum and/or maximum spacing between neighboring agents, ensuring constructional constraints are not violated. The flocking distances can be further adjusted to provide for material efficiency. By raising the limit on the minimum rod length, it is possible to get more surface coverage out of a set of agents producing variations in material efficiency.

[0050] Along with the possible limitations on rod length, since the space-truss uses an offset geometry (described hereinbelow), there are limitations on the maximum angle between the node components of the construction system. The behavior of the agents can be further modified by a rule that keeps the angle between any three adjacent nodes in the resulting space-truss system within a specified range. This range may be, for example, 35.degree. and -35.degree.. However, based on design and structural considerations, any other suitable range of angles can be used. FIG. 2 is a schematic diagram illustrating the behavior of agents 10 of FIG. 1 modified by a flocking rule and angle restrictions within the modeling environment of the design module.

[0051] The CA, flocking rules, and angle restrictions of the design module work internally to provide design direction and internalize construction logic. The software design module can include families of control elements for exerting external guidance on the agents as the agents generate a three-dimensional surface. The control elements include, for example, attractor, avoidance, and plateau envelopes, and these elements can be implemented within the design module operating environment.

[0052] The attractor envelopes can be used to define areas of attraction for the agents, operating like local gravitational influences to pull the agents vertically and horizontally out of their paths. The attractor envelopes are spherical volumes and have a square drop-off of their strength from the center to the outside edge. The attractors provide a high-level of guidance and influence over the shaping of the surface to designers and operate in a similar manner to shaping tools in other generative architectural systems. FIG. 3 is a schematic diagram illustrating the behavior of agents 10 of FIG. 2 further modified by attractors 20 within the modeling environment of the design module. The placement and size of attractors 20 in FIG. 3 is merely illustrative, and attractors 20 can be implemented in any desired configuration.

[0053] The avoidance envelopes define rectilinear volumes of space that are implemented by the design module such that the agents avoid the avoidance envelopes. The avoidance envelopes can be used for defining spatial volumes around which the agent-based surface is shaped, giving a simple means for designers to produce building envelopes. Since the avoidance volumes represent internal spaces around which the surface is shaped, the agents avoid them by moving upwards in 3D space and tend towards producing roof conditions. FIG. 4 is a schematic diagram illustrating the behavior of agents 10 of FIG. 3 still further modified by avoidance element 30 within the modeling environment of the design module. The placement and size of avoidance element 30 in FIG. 4 is merely illustrative, and avoidance element 30 can be implemented in any desired configuration.

[0054] The plateau envelopes define rectilinear volumes within the environment. The plateau envelopes are implemented by the design module such that, whenever an agent passes through the plateau envelopes, the agent is encouraged towards producing a flat, horizontal surface, or "plateau." The plateau envelopes provide a simple means for designers to provide, for example, inhabitable areas, or areas for mechanical equipment, within the doubly curved surfaces generated by the agents. FIG. 5 is a schematic diagram illustrating the behavior of agents 10 of FIG. 4 still further modified by a combination of internal and external controls, including plateau envelope 40, within the modeling environment of the design module.

[0055] In some embodiments, the design module can include a genetic algorithm that allows for the iterative development and testing of formal options for particular design problems.

[0056] In conjunction with the design module, which internalizes the formal and fabrication logic of the space-truss construction system through the use of intelligent agents, the fabrication module of the present invention performs the practical task of converting the surface geometry into a space-truss and cladding. (It should be noted that the terms "fabrication module" and "structure/inventory module" may be used interchangeably herein.) In some embodiments, the fabrication module can be used independently of the design module, if it is provided, as an input, a surface within the formal limitations of the space-truss construction system. The fabrication module of the software performs a preliminary check to ensure that the surface meets the basic formal constraints of rod lengths and angles described hereinabove, and rejects any surface that is unsuitable. After verifying the validity of the surface, the fabrication module provides a model of the rods and nodes and then derives an inventory of rods and node angles. Because the fabrication module accepts only suitable surfaces, the algorithm for translating the surface into a space-truss construction system works with no distortion of the shape, and therefore formal expression of design is not sacrificed for effectiveness of the structure and constructability. FIG. 6 is a schematic diagram illustrating a space-truss structure generated from the behavior of agents 10 shown in FIG. 5 using the fabrication module. In particular, the three-dimensional surface generated by the design module was input into the fabrication module to result in space-truss structure 50 of FIG. 6.

[0057] In addition to providing an output of the resulting space-truss structure geometry, as shown in FIG. 6, the fabrication module provides a plurality of fabrication files used to control cutting devices. For example, the fabrication module can provide three sets of CAD/CAM files for fabrication. The first set of files can be, for example, code (e.g., G-code) and inventory files describing the unfolded geometry of the nodes, the code used to directly control a CNC laser-cutter, 2- or 3-axis milling machine, water-jet cutting devices, or any other suitable machine. The second set of files can be, for example, a schedule of lengths for rods, which can be cut from linear stock of aluminum extrusion. The rods can be cut directly at the factory. The third set of files can be, for example, code (e.g., G-code) and inventory files describing the infill panels. The three files described herein are merely illustrative, and the fabrication module can provide any suitable number and type of files for the fabrication and assembly of the space-truss structure.

[0058] The building components of the space-truss construction system and the software components are related in that the fabrication and construction methods for the space-truss structure inform the constraints and logic of the software, and the digital methods of the software drive the formulation of the structural details. The construction components for the space-truss system have a direct relationship with the digital components of the software modules and the physical manifestation of the design elements.

[0059] The space-truss construction system has a square on square offset geometry, exhibiting a high degree of material efficiency. FIG. 7 is a schematic diagram illustrating a space-truss with square on square offset geometry in accordance with the present invention. FIG. 8 is a more general schematic diagram further illustrating the offset geometry of the space-truss structure. As shown, primary surface or chord 70 is connected to offset surface or chord 72 by a diagonal connection 74.

[0060] The construction system is a two-way space-truss structure, capable of spanning long distances with minimal material due to networked load sharing throughout the entire system. Due to its global rigidity, the necessity for predetermined support conditions is relaxed, while the depth of the space-truss allows for natural insulation and infrastructure raceways, creating a structure that allows for multiple scales of open space to be enclosed with a single envelope.

[0061] Curved structures generally exhibit a higher global rigidity than their planar counterparts, and therefore require less thickness of structure and consequently less material. An aspect of the space-truss system of the present invention is that the software agents (e.g., agents 10 of FIGS. 1-5), seeking optimal configurations, are encouraged to develop curvature in the surface. The space-truss system can undulate between flat spaces where needed, controlled by the plateau elements of the design module, and curved interstitial spaces, in order to give the structure a global rigidity.

[0062] The space-truss system includes nodes, rods, and panels. FIG. 9 is an exploded perspective view illustrating an assembly of such components for the space-truss construction system. In particular, the assembly of FIG. 9 includes a node 80, rods 82, panels 84, and panel cap 92. FIGS. 10A and 10B, and FIGS. 11A and B, provide various views of node 80, rods 82, panels 84, and panel cap 92 as assembled.

[0063] The nodes, as they are located at the highest concentration of shear and moment forces in the structure, can be constructed of gusseted, folded steel plates connected to one another with high-tensile bolts or rivets. Referring back to FIG. 9, node 80 can include multiple node portions 86 (e.g., eight node portions). Prior to being folded for assembly, node portions 86 can be flat plates (e.g., sheet metal) as fabricated, for example, using the specifications from the fabrication module of the present invention. Node portions 86 can include multiple holes 88 to facilitate alignment and attachment of the node portions to neighboring node portions and rods 82. The placement of holes 88 effects the curvature of the resulting space-truss structure. Node portions 86 can be attached to other node portions or to rods 82 using any suitable connection element 89, such as, for example, bolts, rivets, or any other suitable connection element.

[0064] Node portions 86 can include markings at locations 90 at which the fabricated flat plates are to be folded at 90-degrees to prepare for assembly. For example, by marking node portions 86 along the folding locations 90, the node portions can be shipped flat to the construction site, and folded by hand at the site prior to assembly. The ability to fold node portions 86 using hand tools is due in part to the reduced scale of the node portions, as well as the lighter-gauge material used to fabricate the node portions.

[0065] The rods can be composed of extruded aluminum profiles, since the span is modest for a typical space-truss, and the loads are primarily axial. The diagonal rods can be, for example, simple aluminum bars. The panels can be, for example, a wide variety of materials depending on the use of the particular space-truss structure.

[0066] The space-truss system employs node elements constructed of semi-standardized components, allowing for unique configurations of the structure through complex digital cutting methods available using, for example, CAD/CAM technology. By controlling the parameters, such as material -type and thickness and spanning limits, and by fixing bends of the plates to 90.degree., the nodes of the present invention can be formed in a multitude of configurations and can be shipped in a flat, unassembled state. The complexity of the global structural geometry is resolved in local configurations through the space-truss software, by which each node is developed based on its relationship to neighboring nodes. In turn, the capabilities of the design are constants embedded in the logic of the software to allow for realistic design modeling.

[0067] The node, after it has been modeled digitally (e.g., using the design module) and interpreted for fabrication (e.g., using the fabrication module), can be laser cut from steel plate, laser etched as necessary for assembly, and stacked flat for shipment. On a job site, workers can simply bend the node portions by 90 degrees (as illustrated, for example, in FIGS. 11A and B) at the pre-marked locations and bolt the eight bent plates together to form a complete space-truss node. Each plate can be marked (e.g., using laser etching) with a unique identifying number and/or attachment notations during fabrication to allow for simple on-site assembly. The identifying number and attachment notations can be generated, for example, by the fabrication module.

[0068] FIGS. 12A-D further illustrate the interaction between the rods, nodes, and panels of the space-truss structure, and provide dimensioning and performance criteria for the assembly. The dimensions of FIGS. 12A-D are merely illustrative, and any suitable dimensions of rods, nodes, and panels can be used in accordance with the present invention. The rods can be standardized aluminum extrusions in lengths (e.g., as shown in FIGS. 12A-D) designed to accept a variety of cladding options including aluminum panels, composite panels, glass, plastics, fabric, plywood, or any other suitable cladding option. (It should be noted that the various cladding options may be referred to collectively herein as "panels.") The dimensioning and design of the space-truss structure allows for inexpensive fabrication and variability based on local conditions of availability and cost of materials. The software can limit the lengths of the extrusions to those capable under the loading conditions input, assuring that one extrusion will handle any condition. For example, in the case of rods constructed of aluminum alloy material, the lengths can be limited to 100 cm to 150 cm. The software can specify any additional milling of the extrusions to be performed during extrusion cutting. In some embodiments, the plates used to form the node portions can be of a thickness in the range of, for example, about 0.03125 inches to about 0.0625 inches. However, this range is merely illustrative, and the plates used to form the node portions can have any suitable thickness.

[0069] The software of the present invention, according to the material limitations of the paneling material selected for the design, calculates the size of the panels that provide the spatial enclosure. The material type for the panels can therefore, in some embodiments, act to adjust the software design parameters. Different material limitations that would affect the thickness of the cladding panels, as well as the spanning capabilities, can be provided for by changing the basic parameters within the software agents. The details of the structural system are designed to provide for panels of typical thicknesses. The panels can be laser cut and scored in a similar fashion as the nodes, or can be cut on-site as necessary using local materials as available.

[0070] The space-truss construction components can be small and light enough to be manipulated by hand. In such an example, the average rod length can be limited to approximately 1 meter in length, fixing the cladding panel sizes to typically 1 square meter in size. The scale assures that shipping containers holding a large number of components can be transportable by two persons, even over rough terrain.

[0071] The folded steel plate used for the nodes in the space-truss construction system not only allows for simple CNC fabrication, but also produces a lightweight and flexible structural system with a concern for ease of transport and erection. In connection with these factors, the fabrication software can calculate efficient cutting of materials, as well as packing of components for shipping. The structure provides for assembly on site with a minimum of tools by unskilled labor. Thus, the increased erection time often associated with previous space-truss structures is mitigated through the ease of assembly and low-skill level necessary for assembly.

[0072] For ease of site assembly, some or all of the components can be marked directly on the material. An illustrative assembly process includes folding the steel plates and attaching the plates to one another to compose a node. An exploded view of a node is shown, for example, in FIG. 9, in which node portions 86 can be connected to one another to compose node 80. Rods can be inserted along with waterproofing sheets (if desired), and attached (e.g., bolted, riveted) to the nodes in approximate locations. Exemplary rods are shown in FIG. 9 as rods 82. A panel can be placed in site with the appropriate spacing blocks, allowing the structure to be firmly attached in the correct configuration. Exemplary panels are shown in FIG. 9 as panels 84. The panel can then be sealed in place using an adhesive. For example, a one-part silicone sealant can be used to provide waterproofing and structural adhesion. A module of five nodes and its accompanying panel and rods are assembled, and this module is repeated in the sequence developed by the software and ordered in the packing method.

[0073] Since the space-truss is a rigid structure, the underlying components are self-supporting within limitation, thereby allowing for the structure to be assembled without the use of excessive scaffolding. In addition, modifications to the position of the components are possible as the structural sealant is flexible and the panel mounting method allows for a range of setting conditions.

[0074] The space-truss structure can be demounted in a similar method to its deployment, affording the opportunity of recycling and/or reusing some of the materials, relocating the structure, or reusing the structure at a later date. The ability to demount the structure provides additional cost and sustainability efficiencies over traditional space-truss structures.

[0075] Various features of the present invention will be described hereinbelow in connection with the flow diagrams illustrated in FIGS. 13-15.

[0076] FIG. 13 is an illustrative flow diagram demonstrating the interaction of the design and fabrication modules in accordance with the present invention. Design module 102 is implemented to provide a three-dimensional surface model 104. The surface model can be provided as an input to fabrication module 106. The fabrication module can provide, for example, CNC code for a cutting device 108, a bill of materials 110, and a schedule of strut lengths 112.

[0077] FIG. 14 is an illustrative flow diagram demonstrating the generation of a three-dimensional surface model by the design module. Parameters for spacing between the agents are provided using a flocking rule (120 in FIG. 14). Angle limits are applied to the agents (122 in FIG. 14). An example of the application of a flocking rule and angle limits is shown, for example, in FIG. 2.

[0078] An area of attraction for the agents is defined using an attractor element (124 in FIG. 14). An example of an attractor element is shown as attractor element 20 of FIG. 3. A rectilinear volume of space is defined for the agents to avoid using an avoidance element (126 in FIG. 14). An example of an avoidance element is shown as avoidance element 30 of FIG. 4. An area through which the agents produce a flat surface is defined using a plateau element (128 in FIG. 14). An example of a plateau element is shown as plateau element 40 of FIG. 5. As an output, the design module provides a three-dimensional surface model 130 derived from the manipulation of the agents using the various control elements. It should be noted that some, all, or alternatives to the above processes (i.e., 120-128 in FIG. 14) can be used to modify the behavior of the agents and yield a three-dimensional surface model in accordance with the present invention.

[0079] FIGS. 15 and 16 are illustrative flow diagrams, demonstrating the "structure" and "inventory" aspects, respectively, of the fabrication module. In particular, FIG. 15 is an illustrative flow diagram demonstrating the generation of a completed space-truss geometry by the fabrication module in accordance with the present invention. A three-dimensional surface model or boundary edges is provided as an input to the fabrication module (140 in FIG. 15). As shown in FIGS. 1-5 and described in connection with the flow diagram of FIG. 14, the design module may generate the three-dimensional surface model using agents that can be manipulated by internal and external controls. Alternatively, the three-dimensional surface model may be provided from any other suitable source. The fabrication module receives user-specified structural load values (142 in FIG. 15), and the fabrication module receives user-specified structural support points (144 in FIG. 15). Based on the inputs, the fabrication module performs a rigid body structural test for overall structural feasibility (146 in FIG. 15). If the structure is unfeasible, then the module receives adjustments to the surface or boundaries by the user (148 in FIG. 15). If the structure is feasible, then the module generates a primary surface based on the initial geometry (150 in FIG. 15).

[0080] A user can adjust the tessellation and offset settings for the primary surface (152 in FIG. 15). The fabrication module can tessellate the primary surface (154 in FIG. 15), and can create an offset surface (156 in FIG. 15). The fabrication module can create connection members (158 in FIG. 15), resulting in an initial space-truss geometry that includes the primary surface, offset surface, and connection members. The user can visually verify the appearance of the surfaces (160 in FIG. 15). If one or both of the surfaces are visually undesirable, then the user can adjust the tessellation and/or offset settings (152 in FIG. 15). If the surfaces are visually desirable, then the module can perform a finite element structural test (162 in FIG. 15). As a result, the fabrication module can provide a completed space-truss geometry 164.

[0081] FIG. 16 is an illustrative flow chart demonstrating the generation of space-truss construction specifications by the fabrication module in accordance with the present invention. The fabrication module extracts certain elements from the completed space-truss geometry 164 (166-172 in FIG. 16), and uses these elements to generate the specific components to be used in constructing the space-truss structure. In particular, the module can extract polygons from the primary surface of the structure (166 in FIG. 16). From these polygons, the module can generate CNC code for each polygon (174 in FIG. 16), from which CNC code for primary surface panels can be provided as an output 176. (It should be noted that while the figure specifically refers to "GCODE," this is merely illustrative, and any suitable code can be provided for the construction of the various structural components.) From the polygons extracted from the primary surface (166 in FIG. 16), the module can provide a catalog of edge lengths (178 in FIG. 16), from which a schedule of lengths for primary surface struts can be provided as an output 180.

[0082] The module can extract polygons from the offset surface of the structure (168 in FIG. 16). From these polygons, the module can generate CNC code for each polygon (182 in FIG. 16), from which CNC code for offset surface panels can be provided as an output 184. From the polygons extracted from the offset surface (168 in FIG. 16), the module can provide a catalog of edge lengths (186 in FIG. 16), from which a schedule of lengths for offset surface struts can be provided as an output 188.

[0083] The module can extract connection elements from the space-truss geometry (170 in FIG. 16). From these connection elements, the module can provide a catalog of edge lengths (190 in FIG. 16), from which a schedule of lengths for diagonal struts can be provided as an output 192.

[0084] The module can extract points including angles of connected edges and diagonal connections from the space-truss geometry (172 in FIG. 16). From this information, the module can generate a space-truss node for each point based on the angles (194 in FIG. 16). The module can unfold the geometry of each node (196 in FIG. 16), and can optimize the layout of node portions on sheets for minimal material usage (198 in FIG. 16). CNC code for node portions can be provided as an output 200.

[0085] It will be understood that the foregoing is only illustrative of the principles of the invention, and that various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention. For example, although the invention is described primarily in the context of a design module and a fabrication module, this is merely illustrative. One of skill in the art would understand that the software for performing the design and fabrication of a space-truss structure in accordance with the present invention can include one module for both design and fabrication of the structure, or any other suitable arrangement.

[0086] The following references are incorporated by reference herein in their entireties:

[0087] Fischer, T. Burry, M. and Woodburry, R., "Object-Oriented Modeling using XML in Computer-Aided Architectural and Educational CAD," in Tan, Beng-Kiang et al (eds). CAADRIA2000 Proceedings, pp 145-155.

[0088] Fischer, T. Burry, M. and Frazer, J., "Triangulation of Generative Form for Parametric Design and Rapid Prototyping," in 21st eCAADe Conference Proceedings, Graz September 2003, pp 441-448.

[0089] Wolfram, Stephen. A New Kind of Science. Wolfram Media Inc, Champaign Ill. 2002.

[0090] Clarke, C. and Anzalone, P., Architectural Applications of Complex Adaptive Systems, in: Klinger, K., ed., ACADIA 22 Connecting--Crossroads of Digital Discourse, Ball State University, Indianapolis, 2003, 324-335.

[0091] Frazer, J. An Evolutionary Architecture. London: Architectural Association. 1995. pp. 86 and 90

[0092] Reynolds, C. W., "Flocks, Herds and Schools: A Distributed Behavioral Model," in Computer Graphics, 21(4), SIGGRAPH '87 Conference Proceedings, pp. 25-34.

[0093] Testa, P., O'Reilly, U. M., Kangas, M., Kilian, A., "MoSS: Morphogenetic Surface Structure--A Software Tool for Design Exploration," in Proceedings of Greenwich 2000: Digital Creativity Symposium, London: University of Greenwich, 2000, pp. 71-80.

[0094] Chilton, J., Space Grid Structures, Architectural Press, Oxford, 2000.

[0095] Ramaswamy, G. S., Eekhout, M. and Suresh, G. R., Analysis, Design and Construction of Steel Space Frames, Thomas Telford, London, 2002.

[0096] Thornton, W., AMA Institute of Steel Construction and American Institute of Steel, Manual of Steel Construction: Load and Resistance Factor Design, 3rd Edition, American Institute of Steel Construction, Chicago, 2001.

[0097] Aluminum Association, Aluminum Design Manual, Aluminum Association, Inc., Washington D.C., 2002.

Claims

1. A method for designing and fabricating space-truss structures, comprising: providing a three-dimensional surface model for a space-truss structure; and based at least in part on the three-dimensional surface model, generating construction specifications for the space-truss structure.

2. The method of claim 1, wherein providing the three-dimensional surface model for the space-truss structure comprises: generating the three-dimensional surface model for the space-truss structure.

3. The method of claim 2, wherein generating the three-dimensional surface model for the space-truss structure comprises: modifying the behavior of at least two agents.

4. The method of claim 3, wherein modifying the behavior of the at least two agents comprises: providing parameters for spacing between the at least two agents.

5. The method of claim 3, wherein modifying the behavior of the at least two agents comprises: applying an angle restriction to the at least two agents.

6. The method of claim 3, wherein modifying the behavior of the at least two agents comprises: identifying an area of attraction for the at least two agents.

7. The method of claim 3, wherein modifying the behavior of the at least two agents comprises: identifying a rectilinear volume of space for the at least two agents to avoid.

8. The method of claim 3, wherein modifying the behavior of the at least two agents comprises: identifying an area through which the at least two agents produce a flat surface.

9. The method of claim 1, further comprising: based at least in part on the three-dimensional surface model, generating a space-truss geometry having a primary surface and an offset surface.

10. The method of claim 9, further comprising: extracting polygons from the primary and offset surfaces to generate the construction specifications.

11. The method of claim 9, further comprising: extracting connection elements between the primary and offset surfaces to generate the construction specifications.

12. The method of claim 9, further comprising: extracting a node location from the primary and offset surfaces to generate the construction specifications.

13. The method of claim 1, wherein providing the construction specifications for the space-truss structure comprises: providing instructions for a cutting device.

14. The method of claim 1, wherein providing the construction specifications for the space-truss structure comprises: providing a schedule of lengths for rod elements of the space-truss structure.

15. A device for designing and fabricating space-truss structures, comprising: a processor executing an application that is configured to: provide a three-dimensional surface model for a space-truss structure; and based at least in part on the three-dimensional surface model, generate construction specifications for the space-truss structure.

16. The device of claim 15, wherein the application is further configured to generate the three-dimensional surface model for the space-truss structure.

17. The device of claim 16, wherein the application is further configured to generate the three-dimensional surface model for the space-truss structure by modifying the behavior of at least two agents.

18. The device of claim 17, wherein modifying the behavior of the at least two agents comprises providing parameters for spacing between the at least two agents.

19. The device of claim 17, wherein modifying the behavior of the at least two agents comprises applying an angle restriction to the at least two agents.

20. The device of claim 17, wherein modifying the behavior of the at least two agents comprises identifying an area of attraction for the at least two agents.

21. The device of claim 17, wherein modifying the behavior of the at least two agents comprises identifying a rectilinear volume of space for the at least two agents to avoid.

22. The device of claim 17, wherein modifying the behavior of the at least two agents comprises identifying an area through which the at least two agents produce a flat surface.

23. The device of claim 15, wherein the application is further configured to: based at least in part on the three-dimensional surface model, generate a space-truss geometry having a primary surface and an offset surface.

24. The device of claim 23, wherein the application is further configured to: extract polygons from the primary and offset surfaces to generate the construction specifications.

25. The device of claim 23, wherein the application is further configured to: extract connection elements between the primary and offset surfaces to generate the construction specifications.

26. The device of claim 23, wherein the application is further configured to: extract a node location from the primary and offset surfaces to generate the construction specifications.

27. The device of claim 15, wherein the application is further configured to: provide the construction specifications for the space-truss structure by providing instructions for a cutting device.

28. The device of claim 15, wherein the application is further configured to: provide the construction specifications for the space-truss structure by providing a schedule of lengths for rod elements of the space-truss structure.

29. A system for designing and fabricating space-truss structures, comprising: means for providing a three-dimensional surface model for a space-truss structure; and means for generating construction specifications for the space-truss structure, the construction specifications based at least in part on the three-dimensional surface model.

30. The system of claim 29, further comprising: means for generating a space-truss geometry having a primary surface and an offset surface based at least in part on the three-dimensional surface model.

31. A computer readable medium storing computer executable instructions for designing and fabricating space-truss structures, the executable instructions comprising: providing a three-dimensional surface model for a space-truss structure; and based at least in part on the three-dimensional surface model, generating construction specifications for the space-truss structure.

32. The computer readable medium of claim 31, the executable instructions further comprising: generating a space-truss geometry having a primary surface and an offset surface based at least in part on the three-dimensional surface model.

33. Construction specifications for a space-truss structure generated by a method comprising: providing a three-dimensional surface model for a space-truss structure; and based at least in part on the three-dimensional surface model, generating the construction specifications for the space-truss structure.

34. The construction specifications of claim 33, wherein generating the construction specifications for the space-truss structure further comprises providing instructions for a cutting device.

35. A system for construction of a space-truss structure, comprising: a node; a rod; a panel; and construction specifications for the node, rod, and panel generated by: providing a three-dimensional surface model for the space-truss structure; and based at least in part on the three-dimensional surface model, generating the construction specifications.

36. The system of claim 35, wherein the construction specifications include instructions for a cutting device.

37. A node for a space-truss structure, comprising: an upper portion comprising a plurality of plates; and a lower portion comprising a plurality of plates, each plate having a base portion and two end portions folded at about 90-degrees with respect to the base portion, each end portion of each plate aligned with an end portion of another plate, and the base portion of each plate of the upper portion positioned adjacent to the base portion of a plate of the lower portion.

38. The node of claim 37, wherein the upper portion consists of four plates and the lower portion consists of four plates.

39. The node of claim 37, wherein each plate has a notation indicating an assembly configuration of the plate.

40. The node of claim 37, wherein each plate has a marking positioned between an end portion and the base portion indicating a location for folding the plate at about 90-degrees.