LC #42 Pipers Alley

View Full Version : TP collision?

rob rhodes
10-25-2005, 02:30 AM
Hello, Im needing to use collision for a project and i have never really used TP or expresso before. I am emitting a couple of different fruits (many of each) out of a standard emitter with a bit of rotation to look like they are falling. However some of the fruits are intersecting hence the need for TP i think to make sure they don't intersect. The manual seems to go in for more intricate examples which I don't really have time to wade through and try and pick out the relevant bits. Some of the fruits are quite complex like a pineapple for example so im not sure if this will send my PC up in smoke?! I am just after a still image so if the worst comes to the worst I think i should be able to make it editable and manually shift indervidual objects, but i was hoping someone might be able to give me a screen print of some expresso that shows how to achieve something like what im after. Or point me in the direction of a goog tutorial on this

Many thanks, Rob

10-25-2005, 06:59 AM
hard collisions are not possible between particles. You can use the TP Particle Collision preset for this, if your fruits have vastly different sizes the setup can be adapted to take size and mass into account.

10-25-2005, 04:07 PM
Does anyone have a sample of this. Cause I always drive myself bonkers trying to get something like this to work...I invariably roll up my sleeves and just paint out the intersections in Post.

It would be a cool idea if we could bake down the particle solution, and then have the ability to delete or move the intersecting particles.


And yes, the pun was intentional. :p

10-25-2005, 05:38 PM
an example on how to use a collision diameter for this can be found here
The setup uses a Datachannel to store a collision diameter for each particle. The diameter can be set in the modified emitters used.

Hope this helps

10-26-2005, 12:28 PM
an example on how to use a collision diameter for this can be found here .c4d
The setup uses a Datachannel to store a collision diameter for each particle. The diameter can be set in the modified emitters used.

Hope this helps

hi shrek,

it would be realy nice to see that file..., but it seems to be a dead link! I tried twice....

later jan

10-26-2005, 12:43 PM

srek the link was not complet ;-)

rob rhodes
10-26-2005, 04:27 PM
thanks for the link but only half of what im looking for. If you look at frame 38 of the example you should see 2 of the larger balls intersect with each other. I was hoping there was a simple way to stop this so the objects coming out of the same emitter don't pass through each other. Hope thats clearer, Cheers

10-26-2005, 07:34 PM
Self-Collision of particle streams would indeed be nice for things like schools of fishes or other things along the lines of crowd animation.

10-26-2005, 07:42 PM
you can collide particles, just not full geometry of the particles (it's just spherical collisions). use the TPRepulse/Bounce node or the TP Particle COllision object from the object library (now in the browser).

10-26-2005, 08:27 PM
No you can't do that. At least it doesn't work when I try it. You need two seperate particle groups for Repulse/Bounce and Particle Collision. Putting the same group in the two slots does not work.

Also the manual says that self-collision does not work with Repulse/Bounce.

10-26-2005, 09:43 PM
sure you can, works here just fine.

i've got an emitter spitting out particles at a cube which is deflecting them back towards itself and a tp particle collision in there it works just fine, the particles are bouncing off each other, and it works the same if i manually set it up using the pt repulse bounce node and a PPassAB node.

i've not read the manual in years, but i'll have to go and have a look at it, if it says that then it's wrong (i believe one of the old tp example scenes was even using this to pile up particles on top of one another).

10-26-2005, 10:15 PM
srek, why no particle collisions with actual particle geometry?

i've been doing some additional freelance work that needed thinking particles
and almost every scene required some collisions, seems this would be one of the most
valuable and missing things in Cinema 4D to date, besides the out-dated Dynamics system.

10-27-2005, 12:16 AM
maybe Remotions PhyTools with RIS or ParticleSPH simulation is another option.
Example shows ParticleSPH simulation, one standard emitter used.
Works pretty well with convex shapes, no penetration of apples, peaches, strawberry, but don´t use bananas.:D Sor3 460 kB

PhyTools is available as demo or purchase at:


10-27-2005, 10:18 AM
I'm very sorry indeed and I think I need some slaping with big trouts - I forgot to tick the "On" field of Particle Collision :D

I think the manual is wrong...

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