Introduction

In general, in the design of the architecture, the shape of the object designed: home, building, territory, etc. is something that the architect decides from a series of “inputs”. Obviously the structural concept is also one of these inputs. If we are going to build a sports hall we will think of covers on the basis of roofs, large trusses of steel or laminated wood, domes, etc.. But the exact form of the building will never be a direct result of structural loads the building encountered.

In the Tensile Architecture the process is a little different. If you’ve decided to use a type of architecture in which most of the loads are of tension, it is very possible that most of the structural elements are of type cable, foil, tendon, etc. which only support tension loads.

If so, we must devise ways to ensure that at any time (under any type of load) the structure and its elements are subjected to tensile stress. Finding these forms is not always immediate, and the method to achieve this is called Form finding. In reality, there is only one method, but a diversity of them. The most common are given below:

	Geometric method Used in forms where the geometry is known, such as pneumatic covers of spherical, cylindrical, ellipsoids, etc. with a CAD program and not too advanced geometry knowledge, we can easily generate this type of forms.
	Construction method Likewise the formwork for reinforced concrete shells are constructed using properties of ruled surfaces, where moving a set of straight lines on a non-parallel edges produce complex warped surfaces, we can generate tensioned warped surfaces. The case of the hyperbolic paraboloid is a paradigmatic example of this method.
	Modelling method This is the oldest method used especially when the computers did not exist or were not accessible to the designer. Making models with deformable materials (Lycra, latex, etc.) or simply modeling using plaster or clay, warped forms, a tensioned surface is obtained. In fact, this method currently co-exists with others, since many times having a mockup is a necessity for the designer or the client.
	Simulation method It is the most used method today. It uses a specialized software to generate this type of forms. In fact it is to be used in WinTess3. But there are a wide variety of standalone or dependent (plug-ins) applications for this purpose.
	Soap film method This is also a very old method used to fund the research of Frei Otto. Immersing any any rigid or deformable frame in soapy water, we obtain surfaces that are minimal due to surface tension while optimal as tensile surfaces. Obviously they have the serious problem of being ephemeral.