I want to design origami folds parametrically. The best tool I could find is an architectural design software named Rhino3D. The tool is perfect, but is as expensive as it is good.
The best open source alternative I know is FreeCAD. I have used FreeCAD for parametric design of solids, but I don’t find it well suited to model folds in sheets of paper. I couldn’t figure out how to, even if its possible at all.