Help Scripting rod forces

[josemendez]

Well, I want it to bend, but from some defined shape and control the exact shape of the rod.
I think good example is medical endoscope - doctor can bend the tip with control handle, so default "rest" shape becomes different, however the whole thing is still a bit elastic.

Ok, so that's not plasticity after all - there's no external forces involved. You can manipulate the rest orientation of each bend/twist constraint yourself (by writing to their restDarbouxVectors array), or you can use a ObiBone which does exactly what you're looking for: it creates and drives a rod-like structure using a skeleton. This way you can just rotate the skeleton joints to the shape you want the rod to have, and it will try to follow it while performing the simulation.

Actually how rod keeps it's shape? Does it try to keep relative orientations always the same?

For each constraint, it measures the current darboux vector and tries to keep it the same as the rest darboux vector. If you want the nitty-gritty details, it implements this article.

kind regards,