I just wanna show off a little mel I made over the last couple of days. It allows you to create masks based on per vert velocity from previous frame. This allows you to create layered shaders based on vert speed (such as I did on this example) or alter the emmision rate of partciles based of of velocity (whcih is also in the example). Pretty much anything that can use a mask as an input can now use a mask based on velocity as input. Tell me what you think! The only real thing I have left to do is to give you the option for the mask to fade out more gradually instead of abruptly masking when velocity from the last frame is 0. This shouldnt be to bad to put in... I just havent gotten to it yet. I put this in the mel forum area but since so few ever look in there I thought I would throw it up here as it is a finished animation test for a mel script.
By the way the animation, rig and model was created by my co-worker Luis Sanchez. I much appreciate him letting me use it to try the script out on. All I did was add the shader effect, partciles, and basic lighting and rendering.