videle, on 03 June 2012 - 02:40 PM, said:
I am having difficulty controlling the emission of particles from a surface textured with an image. I would like to suppress the emission of particles from points of the surface where the alpha is zero i.e. the transparent.
I have found several threads where texture based particle emission is discussed. Unfortunately none of these threads discuss how to suppress the emission of particles based on alpha.
Nevertheless, I've attached a small scene illustrating my attempt.
1) Mandril.pic seems to be without Alpha so i used intensity (length(color)) to mimic it otherwise it would be 1 everywhere.
2) You need to promote Alpha attrib to primitives (i used average) cause you're emitting from them (and use Emission type = Surfaces (attribute) in Source POP.