Origami folding - kangaroo constraints

22_11_30_origami_module_dp.gh (27.4 KB)

Here’s your definition with both diagonals and planarization added for the quad faces.

However, one thing (not specific to simulation) to point out here is that this shape violates something called the (now proved) bellows conjecture, which says that no closed polyhedron can fold in a way that changes its volume while keeping rigid faces.

So the only way this object can fold is by stretching. This isn’t always a problem - since depending on the material some amount of stretch and flex of faces is usually possible, and there are some great non-rigid-origami multi-stable designs, such as Kresling modules or Tomoko Fuse’s pako pako.

When simulating though, non rigid origami can take a bit more tweaking of the strengths, since you need to allow enough stretching for it to be able to fold, whereas with true rigid-origami you can just make the edge length strengths massively higher than other actuation goals so they become effectively rigid.