View Full Version : Emitting particles from a node?

03-22-2014, 05:17 PM
I have a large ocean displaced with with procedural. I want to emit particles from the peek of the waves. Solving this hasn't been easy for me. I really want to just use a plane emitter, and emit particles based on the displacement procedural. It is very easy to isolate the peeks and make a texture that has everything black and the tips white using nodes. But I have no idea how to get the emitter to emit based on a texture in a node. Possible?

My 2nd approach was collision between the wave peeks and a plane, but that just seems like such a computationally intensive solution. I also had the added trouble of not getting it to work.

My 3rd approach is to use the emitter with a texture for birthrate, and use the displacement texture, but I am convinced that feature doesn't work in the slightest.

Does anyone have any experience doing this?

03-22-2014, 05:57 PM
I don't know how you can do it directly with nodes. But you could render out your peaks as a black and white image sequence from an orthographic camera that is the same size as your emitter. Then use that image sequence as a texture on the birthrate of your emitter. I am able to use textures on the birthrate of the emitter so I think that does work.

Edit: I just remembered that one of the procedural textures in the texture editor is a node editor. So if you use that node editor you should be able to control the particle birth rate with nodes.

Edit2: I just tried it out and I was able to control particle emissions with nodes. There were a few odd things that happened like I had to set the blending mode to subtractive to get it to work and I had to uncheck and check the layer to get changes to the node to take effect.

Edit3: Ben I hate to gush but I loved your animation reel. Was that all done with Lightwave?



03-26-2014, 08:37 PM
Hey lertola2! The animation on my reel is all lightwave except the fluid dynamic smoke on the launch shots. Although I have started to switch over to doing that in lightwave with some success. I appreciate the compliment!

Thank you very much! I just now tried to put in the checker layer like you did and with the birthrate at 0 and the texture, nothing happened. Also with the birthrate at 500 and the texture in there nothing happened either other than random particles, but when I made the checker layer subtractive it worked. I find it odd that the texture doesn't ADD value to the birth rate at those locations, but it is capable of reducing it. Either way, that will work in terms of isolating where the particles come from! Thank you about the information regarding the node editor, I don't know why I have never even noticed that before. When I get back to this shot I'm definitely going to go round 2 with this. :)

Thanks again!