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Tension revisited—3: ForTen 3000

News | January 1, 2009 | By:

An ongoing review of tension structure software.

ForTen 3000 is the latest version of the tensile design software by Italian architect Gerry D’Anza of Baku Group. D’Anza has been developing the software for the past 15 years and it is in use by several design firms, including D’Anza’s own Baku Group. ForTen 3000 offers designers a nearly all-inclusive environment for tensile formfinding, structural analysis and patterning. This wide range of functions makes for a learning curve comparable to other complex 3-D modeling applications, but its capabilities make it a valuable tool for architects engaged in membrane design.

Unlike freeform modelers, ForTen is best approached through a step-by-step process detailed in its user manual and several informative videos produced by D’Anza. The core steps in this process are preparation, formfinding and analysis. Since ForTen is geared toward formfinding and not freeform drawing, the skeleton of the design is best prepared in a modeling application such as AutoCAD® or Rhinoceros.

The main components of this skeleton are the supporting structure, such as trusses and cables, and a boundary line that defines the starting condition of the membrane. Once these basic decisions have been set down, the 3-D model can be imported into ForTen. Each of these elements is then assigned material properties. The software contains an array of materials including cable, steel and membrane materials, and others can be defined by the user. Many properties of each element can be defined, including elasticity, tensile strength and pretensioning. A single button then sets the formfinding process in motion, quickly resulting in a membrane surface. From this point the designer can refine the properties of the various elements and rerun the formfinding process to achieve the desired form.

Included in the software are a variety of visualization tools that offer immediate feedback about the suitability of the structure. Analysis ranges from resultant forces to stresses at each point in the membrane. From these analyses the designer can see potential necessary alterations, such as regions in the surface that may be prone to wrinkling. A patterning tool is also a part of the package, which helps the designer determine optimal cuts for fabrication.

The drawbacks of ForTen 3000 lie not in its capabilities, but in its ease of use. In most software applications there are many unwritten standards, from which ForTen breaks. For instance, the ubiquitous control-s (usually indicating save), here switches the rendering mode. More importantly, the software seems entirely opaque to the beginner: it will yield no results to those who learn software by casually playing. Luckily, D’Anza provides a series of tutorials that guide the new user to success.

For any designer looking for an all-inclusive package to tackle tensile structures, ForTen looks like an excellent choice. The formfinding algorithm solves even highly irregular configurations with ease. Despite various challenges the author faced in learning to use it, only a short period of time was required to produce useful results. The start-to-finish approach of the software should make it a valuable addition to environments that deal with tensile structures on a regular basis. Additionally, the technical nature of the software’s workflow would make it a valuable part of any curriculum teaching tensile engineering.

ForTen 3000 runs on Windows and a trial version is available at:

Aaron Westre is a recent graduate of the Master of Architecture program at the University of Minnesota College of Design. His research interests include designer-computer interface, intelligent design software and emergent systems as a basis for design.

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