So I keep having this problem when I try to make smoke. Basicly it looks like the normals are all wrong on halo material. The parts of the cloud that should be bright are not and visa versa. Either there is something I’m missing from the halo system or my setup is wrong.
Initially, I was stumped by your file. However, after experimentation, I seems to me that the particles are shaded base on their vector relative to the light source, and not their closeness to the light source. For example, if a particle is traveling directly towards a light, it will be shaded as if it receives no light. However, if it traveling perpendicular to a light source, it will be shaded as if it were lighted.
In the example picture, the particles on the right are facing the light on the far right.
The center particles are at a 45 degree angle.
The particles on the left are facing the camera (perpendicular to the light).
Yes thats what I thought. But how do you fix it? This creates a “ring” of bright smoke no matter what the lights do. When I try to use the “vector” option I get weird tangent shader type effects that won’t turn off no matter what I do.
I don’t know of a good way to fix it. You might play around with having multiple lights, so that the particles are lit from multiple sides. It could make it look better, although it doesn’t really solve the root of your problem. Anyone else know how to fix this?
Ken Perlin says to just blur the heck out of a few particles using the Blur node in post-production. See his site; he is a teacher and does a lot of animation research.
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