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It is impossible to work with complex doubly curved surfaces without understanding the geometry or without the tools to manipulate the form of the surface. The surface is represented as a mesh. The representative mesh is analysed using non linear FEA (finite element analysis) to determine the forces in the membrane, the perimeter cables and the loads to the main supporting elements. The elements are usually masts and cables, but beams, concrete members or even timber can provide support. Non linear analysis is used where displacement may not equal the applied force depending on scale. The membrane should ideally have double curvature, as in a saddle, where the centre of radius of curvature in two principle directions is on opposite sides of the surface. This forms a shape known as an anticlastic surface. Tension structures use a double curvature that is anticlastic (in opposite directions), while the air supported structure is generally synclastic (curved in the same direction).
The membrane will be in equilibrium when the radius of curvature of the surface is small enough to resist out of plane forces. The shape can then satisfy both artistic and engineering requirements.The fabric panels are generally laid across the surface in direct alignment with the principle axis of curvature. This ensures that the fibres of the woven base cloth can act in the most effective way.