[ODE] gravitational force / unstable joints

Jon Watte (ODE) hplus-ode at mindcontrol.org
Sat Jul 28 11:53:54 MST 2007

You're giving too little information.

What is your time step size?

How heavy are your bodies?

Are you using single or double precision?

Joints work just fine fine for me in single precision with reasonably 
heavy objects and -9.81 gravity when using 10 millisecond step size 
(0.01) and generally SI units. "reasoably heavy objects" means in the 
range from 0.1 kilograms to 100 kilograms. If you need significantly 
heavier objects, try double precision.


          / h+

Tobias Zimmer wrote:
> Good evening all!
> (At least that's what is in my country...)
> Today I decided to adjust my construct to more realistic parameters. But 
> when
> I switched the worldgravity to -9.81, nearly all joints collapsed!
> That is my biggest problem with ODE, the joints just don't stick 
> together, even
> with dParamSuspensionCFM=1e-5 for my Hinge2.
> Even at a gravitation of -1 I could severe problems with the joints, not 
> even
> my fixed joints stay together! I know I shouldn't use them, but my 
> Universal joints
> danced around like drugged ravers although I set histop as well as 
> lowstop to 0!
> best regards,
> Tobias
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