CAD
Read here about the use of computer-aided design in tensegrity studies. Find also links, procedures and hints relating to the most commonly used CAD tools.
Overview
Computer-aided design (CAD), also known as computer-aided drafting and design (CADD), is the use of computer technology for the process of design and design-documentation. CADD software, or environments, provide the user with input-tools for the purpose of streamlining design processes; drafting, documentation, and manufacturing processes. CADD output is often in the form of electronic files for print or machining operations. CADD environments often involve more than just shapes. As in the manual drafting of technical and engineering drawings, the output of CAD must convey information, such as materials, processes, dimensions, and tolerances, according to application-specific conventions.
CAD is an important industrial art extensively used in tensegrity structural applications. It is also widely used to produce computer animation of such models.
Critique of CAD
Mathematical modelling methods do not replace intuition. Charis Tselentis wrote to Ken Snelson, "The first lesson in Tragwerkslehre (structural) at the RWTH Aachen did not include formulas and calculations. A tall, slim, old German was standing at the podium and was performing a show, bending and pulling rulers, while his body shook with every move. "You have to feel the stress," he claimed. To feel these invisible fibers, that hold the structure together, but at the same time threaten to crush it. I remember Prof.Dr. Krauss every time, when doubts arise about the position of a beam. Because the feeling of the structure is more important than the calculus."
Snelson responded, "I think that what Dr. Krauss was describing, being able actually to feel the forces, is easy for some people but for others it just doesn't come naturally. Having that ability has great advantages." [1]
CAD Software Packages Used by Tensegrity Researchers
Software packages known to be in use by tensegrity researchers are listed here.
Rhino
Rhino is a popular 3D rendering and CAD package. Some members of the Rhino community have published tensegrity renderings and templates.
Rhinoceros Software and FEM
Rhinoceros Software Can Model Tensegrity Structures Using the Rhino-Membrane Plugin. This plug-in enables a finite element approach method, or shape finding, within the graphical user interface provided by Rhino.
See Finite Element Method for more details.
Grasshopper 3D
Grasshopper is a graphical algorithm editor tightly integrated with Rhino’s 3-D modeling tools. Unlike RhinoScript, Grasshopper requires no knowledge of programming or scripting, but still allows designers to build form generators from the simple to the complex. The Underwood Pavilion and the U of Tokyo pavilion are two of many structures that used Grasshopper (along with Rhino and graphic physics engines) to provide the necessary real time feedback in order to design Tensegrity geometries of complex spatial constructs.
To search the Grasshopper site for tensegrity links, click these links for [search], [discussions, or [videos.
link, http://www.grasshopper3d.com/forum/topics/tensegrity-kenneth-snelson
link, http://www.grasshopper3d.com/forum/topics/tensegrity-kenneth-snelson
The following is a list of some users who have posted tensegrity renderings to Grasshopper's online forum:
- Daniel Piker often designs and discusses tensegrity, http://www.grasshopper3d.com/profile/DanielPiker
- Kosuke Nagata posts on tensegrity structures and control, http://www.grasshopper3d.com/profile/knagata
- Piotr Kluszczyński designs tensegrities in Grasshopper, posted a video on form finding, http://www.grasshopper3d.com/profile/PiotrKluszczynski
- Luka Kreze posted two Grasshopper projects, * here and here.
- Alex posted Example of building Tensegrity Kenneth Snelson, images above. http://www.grasshopper3d.com/forum/topics/tensegrity-kenneth-snelson
- Mu has posted many project examples. http://www.grasshopper3d.com/profile/Mu
- Ida, Market project at the Oslo Opera House, http://www.grasshopper3d.com/profile/Ida
- Nenad Kitanovic, tensegrity structure derived by 6 strut octahedral module from center point of it and the center points of hexagonal grid, [see here]. Nenad wrote, a hexagonal grid is used as the base surface. From its center points are calculated vectors for points of upper and bottom layer of two horizontal triangles of octahedra. The balls & sticks are defined by another grasshopper definition and to this he added a tension network.
- Gaetan Kohler of HDA Paris has a user page [here]. HDA Paris specializes in tensile structures, some of which border on tensegrity. Their Orchard Road, Singapore project has a tensile module supporting a glass wall; the module is a type of tensegrity. Kohler posted a video of the Grasshopper models, http://www.grasshopper3d.com/video/orchard-road. There is also a flickr photo set of the project [here].
- Rizz worked on a 'hoopsnake', http://www.grasshopper3d.com/profile/Rizz
- Paul Thorpe researched volumetric tensegrity, and a tensegrity robot simulation, http://www.grasshopper3d.com/profile/PaulThorpe
- Martyna Marciniak explored transforming a Kelvin Cell into a tensegrity structure. http://www.grasshopper3d.com/profile/MartynaMarciniak
- Steven Putt explored generating a Sierpinski Triangle pattern over a surface, within a tensegrity, http://www.grasshopper3d.com/profile/StevenTPutt
Kangaroo Physics Engine
Kangaroo Physics Engine by Daniel Piker works in Grasshopper. Piker posted a walking, morphing 3 strut tensegrity called Kangaroo Physics, http://www.grasshopper3d.com/video/kangaroo-tensegrity
See also http://groups.google.co.uk/group/kangaroophysics
Links and References
[1] Retrieved from Snelson's Facebook Profile, 27 July 2010