Raikiri
Missing graph coloring
Hello, I was looking through your repository as I'm working on implementing this in Houdini.
It looks like this version doesn't use graph colouring (running in groups of points which aren't directly connected)
I found graph colouring is extremely important to get good results. If the points are processed sequentially, points directly connected may influence eachother. Since they're no longer fixed in place, it breaks the assumption used by VBD:
We adjust each vertex separately, assuming the others remain fixed
This causes it to explode more than usual.
It also seems to be using the regular VBD matrix invert instead of LDLT decomposition as used by AVBD. For me it didn't improve the stability, but maybe it will work better for your project
Like you, I found this algorithm is extremely unstable in general. I think this is due to mass-spring energy definition used by TinyVBD and AVBD. This was deleted from the GAIA codebase and replaced with Neo-Hookean energy, probably because it exploded so much.