FumeFX and Mental Ray Displacement

[JuGoran]

Hey, I've been working on a project that is done using mental ray as its main renderer. How do some people composite their FumeFX over their Mental Ray Renders?

The problem I'm having is smoke is being emitted from a character, this character model has a displacement map shader on the character, obviously when I'm doing the smoke simulations, it is calculating based on the mesh BEFORE the displacement map is applied, so when I render out the smoke in mental ray, the displacement adds volume to the model causing the smoke to be covered up by the mesh and doesn't look like the smoke is being emitted from the character.

rendering out the smoke in Scanline does not work because scanline doesn't support the mental ray material displacement, and when comping the smoke from scanline over the mental ray there are problems as the shapes don't match, so it just looks wrong

Any suggestions on how I should tackle this? its quite frustrating,

[Jordan]

i have always just approximated the vray/ mental reay displacement by putting a meshsmooth on my emitter object and adding a standard max displacement. The only issue is that max standard displacement dosent support XYZ space uvs so you have to setup all your mental ray displacement maps with this in mind, either that or do a render to texture. Its a bit of a pain and it would be great if vray or MR had a viewport preview otion in their displacment modifers

[JuGoran]

ya that technique has crossed my mind, but I find in order to get a close enough displacement map the poly count has to be INSAINLY high, which is just unworkable at that point. The reason I went with mental ray Displacement Map is because I can at least get the amount of detail closer to the Zbrush sculpt then just mesh smooth and displacement modifier (which didn't even get CLOSE to the detail)

but the technique might be worth a revisit as before I was trying to get all the detail, but maybe just approx. detail will be enough to help the effect.

thanks,

[Jordan]

you might want to push the mesh in a bit so its always below the rendered displacement, that way it will look like its emitting from the mesh and never from above the mesh.