I could really do with some help with this problem I am having, it was origionally posted in the fusion part of this forum, but I think it may be a FumeFX problem, so I’m posting here now.
Here is a link to the origonal post -
http://forums.cgsociety.org/showthread.php?p=6509336#post6509336
look down to post no.5
Thanks in advance
please, please help. Anybody who has experience of multi-pass compositing with vray and FumeFX
Um, you shouldn’t really be rendering your fume in the same scene anyway.
Should be a completely separate setup with a matted scene. Would eliminate fume as the problem if it is then.
So I can never utilise the GI multiplier in the fumefx render tab? Thought that would be accurate fire lighting. Better than a couple of omni lights which as far as I can think is my other option. How else can I get good fire lighting results in vray? I tried vray sphere lights with a smoke texture applied, it didn’t look any different to omni’s and took longer to render. How does everybody else render their light? How is it done in commercial productions, eg. films. All insight appreiciated.
For the interactive fume lighting, I make a pass with fume not visible to camera, GI on (irradiance map), and put a white material on everything else in the scene… so only stuff that’s lit by the fume shows up, then put that pass over the rest of the scene in the comp.
And for the regular fume pass, you make it render like normal, then make all the other objects vray matte objects with alpha contrib. at -1
So am I right in saying that the ‘white material GI pass’ won’t show up any skylight GI, just the oranges/yellows of my fire GI? Is this also true of using a HDRI for the skylight, which will have more colour to it?
I don’t quite understand what you are asking… the white material will show skylighting if you have a skylight in your scene and turned on… same for the hdri, but if you’re trying to make a lighting pass for your fume you wouldn’t want the skylight on.
Doesn’t the VrayAtmospherePass give me the same result as this? It seems to show me just my fire. Or is there something I am missing with this?
Does this mean the fume GI should be rendered with only primary bounce enabled, or can I use the secondary bounces like the rest of my scene?
I have turned off my skylight and all my lights and I still get GI coming through the windows in my scene, so how do I get just the FumeFX GI?
I’m confused, how can you get GI from a window if skylight/lights/emitters are off? There has to be something emitting GI from somewhere if you are getting GI through a window. Double check your scene. 
VRayAtmoshphere RE simply renders the Atmospherics it does not include GI.
sorry I’m very tired, not been sleepin much cos we have 6 puppies downstairs that keep me up all night. I hadn’t turned off the ambient lighting in the 3dsmax environment panel, that seems to have done the trick
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