(I didn't realize there was such a short time limit on editing posts. A few more thoughts:) A few lessons learned: When using the Alpha channel, less is more. Use as few particles as possible to acheive the desired effect. Rendering the Alpha channel is S-L-O-W. And if you use too many partciles, they end up casting shadows on each other and looking bad. The "size of particle over life" control is very useful. Use it. The shader preview doesn't render the alpha channel when using the Flat Preview. Try using the color White as your base Alpha value and do your mixing and experimenting in the Color channel. Then move the subshader to the Alpha channel when you have things right. A question: In the particle emitter, is there a way to make the particles shoot out to the side rather than straight up? With the smoke I did, I rolled the object over on its side in the assembly room. Then the Z gravity in the emitter affected the particles in the scene's Z axis, not the emitter's local Z. This meant that in the particle emitter I'd have to put the gravity in the Y axis when tweaking values and then move it to the Z axis to see it in the scene. (I hope that makes sense.) If anyone is interested in the shader recipe. I can post it somewhere. - Jasen.