Help Scripting rod forces

[josemendez]

Hi, I used spring to control rod rotation and it works, but I noticed there are strange little vibrations along the rod and after some tests it looks like spring-damp is the cause.
I used some huge values to make rod responsive (1000 stiff, 100 damp), but overall the problem is that if rod twist compliance has specific values it starts to jump between two rotations, kind of, it oscillates, but very fast. I rotate first 10 particles from the left to desired rotation via angularVelocity and I think this force propagates with lag along the rod and makes it twist like crazy. Do you know what I could possibly do to avoid huge or little oscillations? Do I need to control all particles, because other forces fight here?
I thought about using PID controller,, but by looking at this problem I start to think there will be the same issiue, is there anything reasonable to do here?
Just you know this rod has the same mass everywhere, so it's not caused by different masses and attached images repeat every frame.

Hi!

I would need more details to understand what you're experiencing here. Compliance should not affect stability, at least in theory.

I rotate first 10 particles from the left to desired rotation via angularVelocity

I assume the rod is completely straight and that you're only inducing torsion? (I ask because otherwise, you should also modify linear velocities to ensure no internal tension is generated along shear/stretch directions).

Would it be possible for you to share this setup by sending it to support(at)virtualmethodstudio.com so that I can take a closer look?

kind regards