"Tim Nikias" wrote:
> Particles fly in parabolas as gravity affects them
> squared, not linear, so how do you actually calculate
> rebounces with trace()?

I/O based particle systems work fundamentally different than your particle
system. I/O based systems cannot know the point and location of a collision
before it actually occurs. They calculate the path of each particle by
taking very small steps forward in time, repeatedly, and calculate the
forces each particle is affected by for each step (such as gravity). The
smaller the steps, the better precision.

Gravity is only linear (in the typical environment), but as it's added again
and again for every step, the effect is squared.

Trace is done for every step in the direction the particle is flying.

> For one, you could shoot several trace()s for the
> particle while it moves on it's path, but what, for
> example, you shoot it up at a ceiling?

Yes, what about that?

> You'd have to check upwards for that, not the
> direction of flying. (Hope I'm not misunderstood
> here... ;)

If the above didn't explain it, please ask again.

> My question is, what do you guys do in order to get
> exact results (or near-exact results)?

If the above didn't explain it, please ask again.

Rune
--
3D images and anims, include files, tutorials and more:
Rune's World:    http://rsj.mobilixnet.dk (updated Nov 5)
POV-Ray Users:   http://rsj.mobilixnet.dk/povrayusers/
POV-Ray Webring: http://webring.povray.co.uk

Post a reply to this message