View Full Version : how to avoid light and shadow leaks with Mental Ray

09 September 2004, 03:34 AM
Does anyone have and tips on how to avoid/get rid of light and shadow leaks when rendering indoor lighting with Mental Ray? It seems that now matter how I model my indoor space there is always light and shadow leak....any ideas on how I can fix them?


09 September 2004, 04:31 AM
For the Geometry: Build things like walls as closed, three dimensional forms, the way they really are. Walls with no thickness would always cause problems. Group things intellegently - like westwallgroup with the west wall and all attached windows, doors, fixtures, etc. That way you can link or unlink lights to them when needed.

On the lights: Use spot lights, focused just on the area they need to illuminate, and make sure the dmap bias is appropriate to your scene scale. If you're using photon mapping, sometimes you need more photons in order to get them small enough. Thicker geometry can help with that, though.


09 September 2004, 05:24 AM
Those are some nice suggestions jeremy, I'll have to give them a try in the future.

For a quick fix, I just create a blocker poly plane. What I mean by this is; where every I see internal light leaking in, I just add a poly plane between the exertior light and the exertior wall. It pretty much always fixes the problem.

Hope this helps.

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