View Full Version : Particle emitter based onanim surface height

11-03-2002, 07:20 PM
If I have a surface with high points and low points and those points are animated so the high points are constantly changing. How do I get the particles to emit only from the high points from the surface for that given frame?
First I tried using a simple gradient based on Y distance to object for the birth rate. That bonked.
Then I tried what the manual suggested by getting them to emit from a collision object.
What I did for this was have my animated surface act as a surface emitter for the nozzle. Then under Generated by I set it to collison event. I then finished setting up the particles for the emitter as normal. Next I added a collision object which I set the type up as a plane. Then set the mode to event, although I think I want to set it to erase. I then changed the radius/level so that it would be at the height that I want the particles to begin from the surface. Then I generated the particles with the FXstart button just to be on the safe side. That did not work. I tried parenting the collision plane to the surface and then changing the emitters nozzle to parent-collision and that also did not work .
Any clues to what I'm doing wrong?

11-03-2002, 07:40 PM
Need to set the collision object plane to erase and position it just below the surface so that only above will produce particules.
The only way a gradient will work is that if your emitter object has differant colors that match where you want the particules to emit from,using that it would work planer gradient.

11-03-2002, 07:53 PM
you could make a white to black gradient in photoshop then map it to the Z axis - the trick is to turn on world coordinates so its stuck to the world, then only the high points will emit particles. i used it on a proj lately & it works great.

11-03-2002, 11:19 PM
Thanks for the replies. I finally gave up and went outside to play in the snow with my Huskey. After through a few snowballs for him I realized that I was looking at the problem backwards. I changed the surface to the collision surface and the plan to the emitter. Now she works just the way I wanted.
Thanks again.

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