[Feature Request] Alpha -1 for fire and smoke

[Jordan]

It would be great to have some options for using fume as matte objects. Im thinking a spinner to set the smoke alpha to -1 and the fire alpha to -1 and also a matte checkbox so no color gets contributed to the render.
This would be great for getting very accurate mattes of particle systems and even other fume grids that need to be comped through a fume grid. As we are working on a fume heavy stereo project we need really accurate mattes. At the moment we are having to render the fume grid by itself, then in the particle system pass we need to copy the grid, and make all the fume colors black then use a multimatte render element to get a proper alpha of the particles. If we were trying to render a fume grid matted by another fume grid we would end up with another pass and more copies of the grids to rebuild an alpha.
Ive tried getting the Materila ID out of fumeFX into a render elelemnt without success.

[sitnisati]

Hello Jordan,

I will see what can be done - so you'd like not to render color at all, but to render alpha ?

Kresimir

[Jordan]

Id like it to work like a matte object. So it would render as if it were black and render with -1 alpha, so it cuts out the alpha from other objects it occludes. Similar to what the Matte/Shadow material would do in scanline, or when you check matte object and set the alpha to -1 in the vray object properties.

[sitnisati]

Hello,

Thanks for the feedback. I will see if this is possible at all.

Kresimir