Run Physics simulate several times，get different Results，why？

Gaming and Visualization Technologies APIs Physics Modeling (closed)
1

A ball drop from somewhere,when stopped,the position was different in every simulate. code as bellow:

SkinWidth = 0.025
G = -9.81

//create scene
…
NxReal myTimestep = 1.0f/50.0f;
gScene->setTiming(myTimestep / 4.0f, 4, NX_TIMESTEP_FIXED);

//create actor
…
while(1){

    gScene->simulate(myTimestep); 
    gScene->flushStream();        
    gScene->fetchResults(NX_RIGID_BODY_FINISHED, true);

}

2

Because PhysX SDK does not provides fully deterministic simulation.

3

I don’t know if that’s really the case here. PhysX determinism is good enough to repeatedly simulate with reasonable accuracy a ball dropping on a plane, provided that . Please provide more details; results would be useful, I don’t see them in your post. Also, to compare one run to the next, you should re-initialize the SDK and scene to make sure you aren’t retaining some sort of internal state from one run to the next.

Thanks,
Mike

4

yeah!re-initialize the SDK and scene before simulate ,i got same result.
Thanks MikePhysX.