Problem with Passes

[voxel3d]

Hi guys... I'm having a problem rendering in passes, for some reason the GI pass isn't correct... In my efforts to see what was going on I deconstructed the passes from a full render using the rest of the passes which at least looked correct (I took the final render and subtracted from it the Reflection, Refraction, Lighting, Self-illumination and Specular passes which according to my math should give me the GI pass). The result I get is the left-hand image, which looks to be right. The image on the right is what the rendered GI pass looks like, with horrible bleeding below and above the stage. I've also included what the final image is like.

Any idea why this might be happening?? I'm using nuke 5.1 ple to do the comp, that's why there's all those colored squares there...

Any help would be greatly appreciated,

Jorge

[Morbid Angel]

are you working in linear space? with gamma corrections and etc?

[voxel3d]

Yeah, working in linear mode, saved out as .vrimg and then converted to .exr using vrimg2exr. The only pass that seems to have this problem is the GI pass, the others look correct.

[Morbid Angel]

have you tried enabling raw gi render element, it may sove your problem.

[voxel3d]

OK, I tracked it down... The materials on the offending surfaces (floor and ceiling) were standard max materials, as soon as I changed them to VRay materials it cleared the problem. It's interesting to note that as far as I could tell, the effect of having a standard material would make the GI pass look like the RawGI pass for that surface, which is of course wrong...

I also find it important to note that the effect of having the standard material "bled" through to other surfaces, which got a bit brighter on the GI pass (but not, apparently, on the RAW GI pass)

Maybe a bug? I'm working on max2008 32bit with 1.5 SP2.

Jorge

[Morbid Angel]

well its a known fact, that 3ds max native materials are not fully supported by vray in cases of reflections and physical gi...and also render elements.

[voxel3d]

I guess I should've suspected it earlier, it just threw me off that the rendering result (the final image) would look as expected whereas a single pass would not... Thanks for the tips tho, it helped me figure it out!

Jorge