This is a collection of links to tent and tension structure design softwares, this isn't complete and I'm not necessarily recommending any of these.
- Sailcut - Sailcut CAD is a sail design and plotting software which allows you to design and visualise your own sail and compute the accurate development of all panels in flat sheets.
- Surface Evolver - The Surface Evolver is 'an interactive program for the study of surfaces shaped by surface tension and other energies'.
- douglas zongker - polyhedra models - Nothing to do with tents, but some great cut-out and stick-together models of the 13 Archimedean semi-regular polyhedra.
- ip slicer - A little tool for creating patterns to make the segments you need to assemble a sphere. It does it entirely with image files so you can turn an atlas into a globe etc..
- NJIT - The New Jersey Institute of Technology have a small fortran package for patterning. it doesn't seem to work, but maybe you'll have more luck than me.
- puzzles with polyhedra and numbers - Puzzles with polyhedra and numbers. In this site one can print copies of polyhedron puzzles (for non-commercial purposes only) and one can read several mathematical articles on the subject.
- Vinicius F. Arcaro homepage - Vinicius is a Brazilian engineer developing software for shell and tension structures.
- Taylors - Some AutoCAD lisp routines for manipulating polyface meshes, slicing and flattening them.