Help Obi Bones With Stretch Bones Get NaN Values

[josemendez]

As title I'm trying to set up bones to our character, but it seems that at high changes the bones break completley to NaN Values. If I turn stretch bones off, the bones will still break but be in "no active" mode, to show T pose bones transforms.

Video to show issue
https://drive.google.com/drive/folders/1...x1lAva8Hga

The only way I've found to get a "completley safe" case is to set up "Use Limits" on the Solver to restrict the simulation area.

Hi!

I'm unable to reproduce this, rotating the solver and/or the bone root at high speeds doesn't seem to break anything with the bone settings seen in your video.

Note that non-zero world space linear/angular inertia values (found in the ObiSolver component) can cause instability when rotating the solver extremely fast, since these inject centrifugal/coriolis inertial forces at the velocity level that may become arbitrarily large.

Is this a bug? It feels a bit contradictory to the "unconditionally stable" from documentation https://obi.virtualmethodstudio.com/manu...gence.html.

"Unconditionally stable" means the simulation cannot diverge due to the timestep length being too large, as it is usual with traditional velocity/force/impulse based methods. This doesn't mean the simulation cannot break due to other causes unrelated to numerical integration.

kind regards,