I only started this little test a few days ago so I haven't quite decided on
the final method of collisions, but it won't be a single point. I initially
pre determined the distance the particle would travel, which assumed it
would always land at the same height it launched from. As you can tell this
was a silly way to go about it, but I just wanted to see the ball bounce
damn it! I'll probably end up tracing perhaps 6 rays from the sphere's
surface, one in each direction, then getting the shortest ray and tracing
another set of rays from the half of the sphere of the previous ray. This
would continue until there is either the ray length is 0 (or very small) or
some threshold for the number of rays is reached. Kind of a divide and
conquer thing to help reduce parse time. As for particle particle collision,
I'd like to implement it but haven't thought of any efficient methods for it
yet.

Speed based traces sounds like a good idea. How do you plan on being able to
render from a frame starting from the middle of an animation?

Michael B.

"Tim Nikias v2.0" <no_lights (@) digitaltwilight.de> wrote in message
news:3f606a90@news.povray.org...
> Hm. So you're actually using just a single point
> for your particles, right? Not full fledged object
> collision? (I'd guess so for a particle system, its
> not intended as a pun).
>
> Still, 1000 traces is a bit much, don't you think?
> What I'm planning to do for my next system with
> collision detection is to calculate the traces based
> on distance travelled: every 0.1 POV-Units or such.
> Slow moving particles don't require that many tests,
> as long as I've got some variables to keep control
> that a particle is lying on the floor and just won't
> drop any further.
> Faster particles do require more traces, because they
> might easily pass through a wall from one frame to
> the next. Speed-Based traces will do just that. On
> my next particle system, I won't be doing loopable
> animations, but the system should still be able to
> reparse the simulation in case the render begins at
> some frame in the middle of an animation.
>
> Oh, and does your system handle particle-particle
> interaction?
>
> --
> Tim Nikias v2.0
> Homepage: http://www.digitaltwilight.de/no_lights
> Email: no_lights (@) digitaltwilight.de
>
>

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