View Full Version : Instanced particles collisions

06 June 2008, 08:54 PM

I am working on a clip of some blood cells traveling through a blood vessel and I need to make the blood cells collide with each other as well as the vessel wall. I have most of it working, except I can't quite get the cells (which are a mesh instanced to the particles) to collide correctly. They collisions occur at the center of the particle rather than at the edges of the instanced geometry.

So basically I need to figure out how to stop the blood cells from interpenetrating each other and the vessel wall.

06 June 2008, 10:08 AM
Select your particles, create a radial field, select the particle obj, shift select the field and choose field<use selected as source.

After that go to the field which will now be parented under your particle object, apply per vertex to true, play with max distance, falloff, attenuation and magnitude.

Sounds like fun.

06 June 2008, 05:03 PM
Cool! Thank you!

06 June 2008, 10:06 PM
Hi just one followup question:

I've spent the better part of the day tweaking the settings on the radial field, and I can get the blood cells to repel each other for the most part, but occasionally two or more will still travel across each other as if there were no radial field at all. Is that just unavoidable?

06 June 2008, 11:46 PM
As a starting point try:

Mag 8
Attenuation .2 or 0
Max Distance 2-3

From here you can refine the numbers based on what type of behavior you are seeing.

06 June 2008, 12:01 AM
Higher attenuation will allow particles to get closer to eachother, as will lower max distance. Magnitude will effect the intensity of the reaction.

I also got very good results with

Mag 50
Atten 0.5
Max Dist 1.5

Of course this will vary depending on the size of your geo.

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06 June 2008, 12:01 AM
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