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Featherstone Multi-Body Motor

Posted: Sat Apr 05, 2014 7:53 pm
by CireNeikual
Hello,

I am trying to make a robot with Bullet using the Featherstone multi-body solver, since the generic 6 DOF joints were too weak.
I have the multi-body falling on the ground. I added btMultiBodyJointMotor's in order to try to control the robot, but I cannot figure out how to use it.
The target velocity is accepted in the constructor, but is declared protected? So how do I change the motor?

Thank you for any help you can offer.

Re: Featherstone Multi-Body Motor

Posted: Mon Apr 07, 2014 12:40 am
by Basroil
CireNeikual wrote:I am trying to make a robot with Bullet using the Featherstone multi-body solver, since the generic 6 DOF joints were too weak.
Weak motors sounds like using default settings. Try higher iterations and smaller timesteps, it's not great for performance, but should hold you off until you get things sorted (check MultiBody demo).

Re: Featherstone Multi-Body Motor

Posted: Mon Apr 07, 2014 6:48 pm
by CireNeikual
I have tried all sorts of settings, but the 6DOF joint is way too weak. I got featherstone working, I had to inherit from the motor class in order to change the desired velocity. No idea why this is the case.

Re: Featherstone Multi-Body Motor

Posted: Wed Apr 09, 2014 7:26 pm
by Erwin Coumans
The Featherstone/btMultiBody (and btMLCPSolvers) are relatively new and will be improved over time.

If you have a feature request/improvement, please report the issue in our issue tracker:
http://github.com/bulletphysics/bullet3

Thanks!
Erwin