Reviewed by Aaron Westre
TensileDraw is a new 3-D membrane modeling tool provided by Mehler Texnologies. Mehler is a German company specializing in the production of a variety of coated fabrics for architecture, transportation, sporting and other industries. The software was developed for Mehler by M E+C S.r.l., an Italian company that produces a variety of analysis and form-finding applications for engineering and architecture. TensileDraw is available as a plug-in for either AutoCad® or Rhino. Both are available as free, feature-limited (LT) or full-featured, pay versions. The Rhino LT version is reviewed here.
As with most membrane design software, the designing with TensileDraw follows a step-by-step sequence from defining initial boundary geometry through form-finding. The Rhino version of the plug-in is operated via an installed toolbar or a series of commands. The integrated tutorial window is useful for getting accustomed to the software and a PDF manual also is available. The design sequence starts with configuring “styles” that define the properties of the membrane, borders and cables that will be used in the structure. An initial mesh is then created by selecting a border shape in the Rhino modeling window. Border shapes are drawn directly in the modeling window and any closed polyline can be chosen as a border. An initial mesh is created after parameters such as border style, warp/weft offsets and center point are specified. Radial or rectangular meshes can be created. The resulting mesh can be manipulated like any other geometry in Rhino, such as moving specific points to new locations according to design requirements. Once the mesh is manipulated so its anchor points are in their correct positions, these points are fixed in place. Form-finding calculations then shape the membrane according to the material parameters and forces defined by the user. When a suitable form is found a single command creates the surface planes of the membrane in Rhino.
The form-finding process can be repeated as many times as necessary in TensileDraw. Anchor points can be moved at any point and the calculations re-run to see the results. Quick iterative cycles are easily achieved since the initial setup steps are bypassed. Final designs can be further analyzed by having TensileDraw generate a report with measurements, stresses and tensioning requirements.
TensileDraw has a few limitations that may lessen its suitability for some purposes. The LT version lacks features such as defining boundary joints and more advanced reporting and curvature analysis. It also limits the number of nodes in a structure to 400, which reduces the accuracy of the membrane surface modeled. The full version of the software addresses these limitations, but is quite expensive at 3,500 euro.
One of the primary advantages of TensileDraw over stand-alone applications is the ability to work with the created geometry directly in the Rhino modeling environment. This eliminates the need to export geometry for further manipulation or rendering in another application. For instance, using the Rhino’s built-in curvature analysis tools, designers can get rapid feedback on potential problem spots in their designs. Rhino also offers several fabrication-oriented tools that can dovetail nicely with designs created in TensileDraw.
Overall, TensileDraw offers the advantages of rapid form-finding, easy iteration and full integration with familiar modeling tools. Installing the free version is recommended for designers looking for an integrated solution.