David Buck wrote:
> 
> >
> >
> >Hello!
> >
> >Have anyone figured out how to use the ElastoLab physics package? I would
> >like to try it with a simulator I am working on but can't figure out how to
> >set things up. Is there any good examples for this somewhere?
> >
> As Karl said check out the testcases in the class
> SimulatedPhysicsTestcases for examples.
> 
> >Do particles collide?
> >Can you have objects other than round particles? For example a simple
> >square as a physical object?
> >
> >Thanks! Johannes.
> >
> <the short answer>
> 
> No, no, and no.
> 
> <the long answer>
> 
> Particles don't collide because the math gets too hard.  Physics is easy
> to solve when the functions are smooth and continuous and there are no
> sudden changes.  With springs and elastics, you can step forward at 0.1
> second intervals and accurately predict where the particle is going to
> be.  With collisions, you (in theory) have to reduce your step size
> suddenly to 100 microseconds or smaller to figure out how the collision
> occurs.  After the collision, you would have to return the step size to
> something bigger in order to calculate quickly enough.

A simulation that changed the step time would be interesting, do you
know of any such implementation ? The simulation would be more 'real' 
in the sence that real object move, don't jump a longer and longer distance.
This implementation would have it's own set of problems but solve others.

Karl