View Full Version : Particle collision erase driven by texture or weight map possible?

06-17-2013, 04:52 AM
I have a scene consisting of particles colliding with a sphere and the mode set to erase. Is it possible to have where on the sphere they erase/die influenced by a procedural texture or weight map? If this is possible could someone please suggest how I set this up.

Thanks in advance,


Areyos Alektor
06-17-2013, 06:27 PM
In "Modeler" you select the polygons (or points) you wish to use in your simulation, and then you go to "File" and you use the "Section" part. In the "Layout" you activate "Collision" on this new object. And in "Object Properties" / "Render" you hire "Unseen by Camera".

06-18-2013, 02:17 AM
Thanks for the suggestion. I was hoping for a more flexible solution though. Ideally using a texture that could be animated to drive where on the sphere the particles die and have that change over time.

06-18-2013, 07:18 AM
I've just come across a potential solution which i'm trying to test now. Might not work though. Once Collision is set to Erase i've clicked on the Envelope button and noticed in modifiers there is a Textured Channel Scale. From there I can select a procedural texture. Not sure yet if this is going to give me the result i'm looking for. Testing now.

06-18-2013, 11:28 AM
I've just come across a potential solution...... Testing now.

Did it work?

If not, how about this....

Using the surface texture in the HV dissolve texture channel..... important, world coord checked.
(I'm sort of doing the opposite of what you stated, but its the same result right? Instead of erasing what I don't want, I'm only having what I do want "stick".)


06-18-2013, 11:55 AM
Didn't have rt shadows on. Surface setting on HV still renders out a shadow, even when dissolved?? (I must be missing something simple?)

Volume and Sprites work fine .....
(sorry, no weight map option this way, that I can see)

06-18-2013, 01:27 PM
Thanks for the suggestion Joe. I'm away from my computer so can't test this out properly so apologies in advance if this is a dumb question. Does your technique only affect the HV but ultimately leave the original particles intact? The reason I ask is that I need the particles to work with Turbulence FD. If your technique is also affecting the particles then great.

06-18-2013, 01:50 PM
If open GL is any indication, the particles are still there (below). I guess you could also use particle size as well (haven't tested that but maybe that would get rid of the shadow issue with "surface" HVs.)

Oh, and no weight map per se, BUT you can use a UV (so.... use Weight to UV).

Again.... I think. ;D

06-18-2013, 01:50 PM
Hmmm, sounds interesting. Will try it out in the morning and let you know. Thanks!

By the way to answer your question, I haven't managed to get the Texture Channel Scale modifier working the way I hoped it would yet.

06-18-2013, 01:53 PM
Ha!! We posted at the exact same time.... never seen that before. :D

Just making sure you saw my post above yours.

06-18-2013, 02:05 PM
Lookin' pretty good on HV size too. And as suspected, no more shadow issue with surface HV. :thumbsup:
A few small artifacts, but hopefully that's just fine tuning.

(my dyslexia might have kicked in.... might have been thinking of UV to Weight. Don't know if it goes he other way. But hey, you can use a UV which you can paint the same anyway.)

06-18-2013, 03:33 PM
You could use two different layers to make your sphere, and only have one layer kill them?

06-18-2013, 10:33 PM
Quick test with some clunky lookin' voxels.

Initial voxel impact is only on turbulence procedural.
Then animated with input from procedural (waves) "morphing" into a third animated procedural (spiral).... all while still respecting the initial "safe area"(which could be animated too).


06-19-2013, 05:29 AM
That test is looking really nice! I managed to recreate your technique. The problem for my purposes is still that I need something that affects the particles themselves. Since I need the particles to be used with TFD. I'll keep on truckin' though. Maybe the solution lies back in the turbulence FD settings.

06-19-2013, 06:58 AM
ahhhhhh.... for some reason I got it in my head that u did NOT want the particles to be effected. Okay. Back to rumination. :)