Camera Space vector-coloring compound?

[forsgren]

Hi, Im getting into emRPC right now, I'm in the prestages of production, and one of the things that I really must have is vector -shading that goes together with reelsmart motion blur and emRPC.

Problem is, I cant really find any way to color particle based on velocity - In camera space. I've started tinkering with a home brew solution myself. But time is running short and if there is a compound that does the trick already, it would be really awesome.

[Hirazi Blue]

Something like this maybe, or this one (requires Area logon)?

[rray]

(just saw Hirazi's post which solves that, posting nevertheless...)

You could try this :
1. Extract the rotation from the camera "kine global" matrix (using matrix to srt)
2. Invert that
3. multiply the velocity vector with the matrix resulting from step 1&2

This should put the velocity vector into camera space, at its current location. After that it should be just a matter of rescaling the result's X and Y components to get the color.

Problem with that approach is that vectors will be a little off the further they're away from th FOV center (edit... above post takes care of that )

another edit... I just noticed in the article Hirazi linked too I'm credited too much ;) ... most of the math stuff I did in that plugin is based on code by Glen Frazier.

[forsgren]

It worked like a charm. Thanks alot guys.