todays spam: I'm trying to render some lighting to diffuse, using mental ray with an image based lighting setup. just plonked an image into IBL, turned on global illumination and final gather, thats about it.
it renders nice but the transfer maps render comes out black. if I stick a light in the scene the transfer maps picks up the lighting perfectly. is IBL not supported by transfer maps?
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Honestly? I have never tried this myself and was waiting to see if somebody else responded - but have you made sure you set the Normal Direction to Surface front? That is the only reason I can think of if the you just get black.
Edit - yea I'm getting the same thing when using Transfer maps on a sphere with IBL.
http://www.alexmunn.com/html/class_levels_shaders.htm
Surface Sampler doesn't seem to support Mental Ray
edit: by the way I did manage to light a scene with an image without using IBL, I plugged an image into diffuse and illumination on a lambert, increased the colour gain and using FG/GI it seemed to work ok. but that didn't solve my problem of course
oh and is there another way to light the scene with an image other than IBL?
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Absolutely. IBL isn't much more of a node that creates a sphere and the relevant attributes. You can do it manually no problem.
the main point of doing this is so I can, for example, create some hi-poly geom with nice materials etc, light them however I want and bake to a low poly object. I like the flexibility of using images to light the scene, I'm sure I could make do with standard lights but I want to rule out this possibility first
so basically I'm doing a test with some random mudbox doodle, I create a big sphere, invert the normals and apply a picture in diffuse and ambient colour, turning on GI and FG. render looks nice and soft and cool
I set up the transfer maps with high and low poly, using lit and shaded, and render it off- but that comes out black. if I stick a light in there, just the light gets rendered. I've tried sticking a few different materials into the custom map slot, but to be honest I don't have a clue what I'm doing there and get some pretty funky results.. some of them do have the colours of the environment just messed up (black patches, white patches, not actually looking like the high poly). Still the custom slot seems to be the closest I've managed
doh I meant to spent today working on dom war and this bugged me so much I havent done anything else
After that you can bake the texture to the lowpoly version via surface sampler.