I have a particle system on a curved model. I want to have the particles only show up near the edges, at glancing angles. This means I have to have them only be created on faces with a glancing angle above a certain amount, or have them present but render as transparent. Using a texture to control their placement does not work because I need to be able to turn the model.
Is there any way to do this?
If I could use the emitter's normals in the particle's textures, that would be the most simple. But there doesn't seem to be a way to do that.