Really this is more a geometry question than OpenSCAD but I know you're a knowledgable lot. I've recently been playing with creating nets of solids with non-planar faces. When folded, such nets result in curved surfaces, but as polyhedra, the non-planer surfaces are minimally triangulated. <http://forum.openscad.org/file/t229/random-n-prism.png> When constructed in a 2-D rigid material like card, all surfaces assume curved shapes, though these are not necessarily uniquely defined - some faces are bi or multi-stable indicating multiple solutions. <http://forum.openscad.org/file/t229/rpenta-r.jpg> I'd like to find some optimisation method which would produce a triangulation of the solid which would satisfy the fixed edge length constraints whilst minimising curvature (or something like that) Any pointers? -- Sent from: http://forum.openscad.org/