Hi. I’ve been running into this problem for a bit, and haven’t really found any proper solution.
Scene:
I have a small scene, where is a shot glass that has a small thing burning inside it. I wish to get a picture with alpha channel for post production. The glass is on top of a “table”, but all I want is the shadows and caustic effects. Scene has 2 standard lights. The shot glass I want to have a enviroment map for more interesting look. The smoke is visible inside the glass, and I want it to be reflected and refracted by the glass. Ok, now you should have some sort of idea what I’m going after. For the problem part now.
Prob:
First thing I did was to add a “matte / shadow / reflection” material for the table top. Then in it’s parameters I added to the Camera mapped background slot “Environment / Background switcher”. In switchers parameters I set the “background” to mid-grey and to the “environmet/reflections” I placed a HDR bitmap. And then I instanced the “switcher” to the “environment map” in the Environment menu. AFAIK this is the correct way to do this in MR to get the alpha channel work properly for the matte/shadow/reflection material.
Result:
The Fume FX grid shows the reflection bitmap, and nothing else. (no matter if I choose a color for the reflection instead - then it shows the selected color). Alpha channel works good for the rest of the image, except for FUME, which doesn’t show up in alpha at all… In RGB image the FUME grid is visible (and I mean the grid box, not the effects) for the parts where the table top (that has matte / shadow / ref material) is behind it.
Only solution to get FUME render properly so far I’ve come up with is:
Remove BG switcher from environment -> no good alpha channel for post pro -> not the result I wished for. So basically if I did the BG in photoshop and used it in Max as a real backgroud image, I could basically get what I’m wanting (as then I wouldn’t need any alpha channel for my image…) But I really wish to know if there is a way to get this working.
What to do? How can I get the matte / shadow / reflection work with FUME FX in MR so that I get proper alpha channel for the rendered image?
Any bits of info or ideas are more than welcome. Thanks.