Pheonix Sim Multimatte?

[Bertjenkins]

Hi - How do I set object ID for a pheonix FD Sim in Maya, in order to isolate the sim with a multimatte?? I have tried to put the sim in a group and add a vray attribute, as I saw somewhere mentioned in the forums but it's object ID colour does not show up in the multimatte render..

[georgi.zhekov]

Hello,

If you are trying to render Fire/Smoke simulation - make sure you are using Volumetric Geometry render mode.
For the Mesh mode it should work out of the box.

[Bertjenkins]

Hi Thanks. I've switched it to volumetric geometry but I get very weird intersections.. there is a line where the smoke touches the ground. Any way around this?

[georgi.zhekov]

Make sure to raise your Max Transparency Levels option in V-Ray. This should fix those.

[Bertjenkins]

In the mean time I have used volumetric material id and it works fine.

[Bertjenkins]

Missed that, thanks. I will try to adjust the max transparency levels. Just out of interest ...is there a difference in speed/quality when using volumetric geometry? Volumetric with material ID does what i need, but is volumetric geometry preferable?

[Svetlin.Nikolov]

Hey,

No. It's slower than Volumetric and does not support the default Approximate Scattering (under the Smoke Color rollout), so it defaults to Disable scattering which makes the smoke darker.

If possible, render in Volumetric everything except one final pass that you collect the render elements from.

Cheers!