To freeze the particles you can disconect them of the emiter in the dinamic relationships window or delete the emiter.
If you have crashing problems you should try sprites, they are very light to render.
edit:
Wow, this asteroid goes directly to my head
Here's what I'd want to use for a comet. They are nParticles. These I'll have to figure out a way to attach them to the comet body and have them emit as the comet moves.
The cosmic dust clouds need to sit still and I'm not sure which type of particles to use to get irregular cloud-like shapes.
The asteroid pic isn't mine though, it's just a picture I've shown as example.
Here's what my Earth looks like at this point. It's still not light blue enough though. I want it to look more realistic, the one in the tutorial doesn't have that light-blue tint going around it.
Last edited by SilverFeather; 20-12-2011 at 01:25 AM.