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View Full Version : Fire particles emit from shader/specular?

Arcon
07-15-2009, 08:40 PM
I've made some fire particles emit from a surface and tweaked it to the style i want, but i realized something that would be really cool is if i could get the particles to emit from the specular or glowing areas of the shader, rather than the surface itself. this would make it look more like the object is generating the fire & pulsating with life.

i'm not an FX animator by trade but a generalist, so this is a bit out of my area lol, any advice on how to set this up would be awesome :)
Aikiman
07-15-2009, 10:12 PM
Im not sure you can use the luminence value of your shader to emit from but you can use the light and dark values instead if you get my drift. If you plug a texture into your emitter you can emit from light or dark that way. You can even animte your texture and have the surface emission change.
Arcon
07-16-2009, 12:00 AM
hi jeremy - thanks heaps for you reply :) the texture is a 3d animated volume noise, so as per your suggestion i plugged the outAlpha of the texture into the rate of the emitter... was this the right connection to make...? it looks quite cool but its hard to tell if its emitting from the right places, i guess that could be because of transparency & size settings which i'll have to tweak. i had to use a multiply node to scale the output up by 1000 before i really saw it lol.
Bonedaddy
07-16-2009, 01:25 AM
You could bake out a map and reproject it from the camera to get it to emit from certain points. While a light sampler would create the correct emission, it couldn't factor in specularity, I don't think. Reprojecting is the way you'd want to go in that circumstance (especially if, say, it's a model with a bump/normal/displacement map).
Aikiman
07-16-2009, 07:39 AM
hi jeremy - thanks heaps for you reply :) the texture is a 3d animated volume noise, so as per your suggestion i plugged the outAlpha of the texture into the rate of the emitter... was this the right connection to make...? it looks quite cool but its hard to tell if its emitting from the right places, i guess that could be because of transparency & size settings which i'll have to tweak. i had to use a multiply node to scale the output up by 1000 before i really saw it lol.

Down the bottom of the emitter attrs in the AE, theres an input for a texture under texture rate. You can dump your texture straight into this, it connects the outColor to the textureRate, and click on enable texture rate. To be honest im not sure if it works with 3D textures.
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07-16-2009, 07:39 AM
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