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Transmission + Bump

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Hi all,

I wonder if someone can point me out a way to work around this issue. I’m trying to reproduce a spongy material that’s part of a woman pad (don’t laugh… someone has to do those animations as well, after all ).

I’m having issues when I combine raytraced transmission with bump maps. It looks like the areas where the bump is acting don’t get the transmission calculated for them.

Here’s an example of what I’m saying:


In the first two images (the second has GI light turned off to highlight the issue) I have a transmission thickness of 0.013. That’s what I would want as it very much looks like the behavior of the real object. Problem is that all the areas where the fractal noise and erosion bumps are acting (it’s 3 shaders piled in a reactive sequence… don’t know if it can matter) seem to be impenetrable to transmitted light.

As if the raytraced transmission light rays fail to pass through areas with bumps.

On the third picture you can see the effect of reducing the transmission thickness to 0.003. It looks like the best thing I found to keep the bump and at least a light transmission thin line. But I’m loosing a lot of what I’d want.

Is there a work around? Is camera supposed to behave like this?

Any advice is appreciated,


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Hi, rdm, All

More tests are needed. First test: direct light only (no GI) without transmission. Second one: same but with transmission 0.013. If possible - please post and don't worry how they look, it's for testing


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