Restitution dependend on timestep
Posted: Fri Sep 01, 2017 10:01 am
Hello guys!
I've been experimenting with bullet and came across a problem I can't explain it and I can't find any information on the problem.
My setup is as simple as possible: a small box and a small ball falling on a fixed large box. Restitution values for all objects are 1.
Everything seems fine when I run the simulation slower than 500Hz (stepSize > 0.002). If I go above 500Hz, the ball suddenly doesn't work correctly any longer. It seems to loose energy, while the box is still behaving correctly.
Sphere z-Position at 400Hz (blue) and 500Hz (red)
Deactivating split impulse adds energy to the system as expected, independent of step size.
Friction parameters have no effect.
Number of iterations has no effect.
Changes to any ERP parameters have no effect.
It seems to be solely dependent on the real step size, using subSteps doesn't change the behavior ("real step size" = fixedStepSize/numSubSteps).
Shouldn't the simulation be more accurate at higher frequencies?
If there is any additional information I can give you please let me know.
Cheers!
I've been experimenting with bullet and came across a problem I can't explain it and I can't find any information on the problem.
My setup is as simple as possible: a small box and a small ball falling on a fixed large box. Restitution values for all objects are 1.
Everything seems fine when I run the simulation slower than 500Hz (stepSize > 0.002). If I go above 500Hz, the ball suddenly doesn't work correctly any longer. It seems to loose energy, while the box is still behaving correctly.
Sphere z-Position at 400Hz (blue) and 500Hz (red)
Deactivating split impulse adds energy to the system as expected, independent of step size.
Friction parameters have no effect.
Number of iterations has no effect.
Changes to any ERP parameters have no effect.
It seems to be solely dependent on the real step size, using subSteps doesn't change the behavior ("real step size" = fixedStepSize/numSubSteps).
Shouldn't the simulation be more accurate at higher frequencies?
If there is any additional information I can give you please let me know.
Cheers!