[ODE] Particle simulation

[Ignacio García Fernández]

El Lunes, 26 de Febrero de 2007 11:25, Bram Stolk escribió:
> Ignacio García Fernández wrote:
> > Hi!
> >
> > Do anybody have any experience on simulating particles (punctual masses)
> > within an ODE simulation?
>
> I think you would just create a body without associating geometries
> with it.
>

Yes, but what about the dynamic part. Application of forces would always be 
done in the center of mass, but the equations related to the rotation would 
still be there. This makes a considerable amount of unnecessary computations. 
If you use true particle dynamics (only trslation, no rotation, mass matrix, 
etc.) it would save time, and probably would give stability to some 
simulations.

I will do it outside ODE, with its own numerical integrator and so. I wanted 
to know if any effort is ongoing in order to do this within ODE (perhaps I 
could help).

Also, any idea of how to do it can help me, and do it myself (i can't promise 
anythig!!).

> Your particles will not collide with your world though.
>
> You would need to write custom collision detection by intersecting
> a line-segment with the world. The line-segment would have endpts
> p0 and p1 which is the particle pos at t0 and t1.
> If the segment intersects the world, you need to do collision
> response by creating contact joints.
>
> Come to think of it... such a particle program would make a
> nice addition to the demo collection in ode. E.g. simulate
> a water-hose that topples some stacked objects by spraying
> particles onto them.
>

Yes!! It would be nice!

Thanks a lot!

Ignacio


-- 
May the source be with you                                     
---------------------------------------------------------------
Ignacio García Fernández                  Instituto de Robótica
ignacio.garcia_at_uv.es                 Universidad de Valencia
http://robotica.uv.es/~ignacio/                Tlf. 96 354 3671