Mental Ray Normal Map Self-Shadowing?

kodde

Does anyone know any way to get normal map self-shadowing to work with mental ray? With Depth Map Shadows is preferred.

I am trying to come up with an alternative to baking ambient occlusion in Maya.

Thanks.

frubes

are you talking about being able to get the bump detail out of your normal/bump maps and into and ambient occlusion pass?

kodde

Not really, forget about ambient occlusion for the moment.

What I want is shadowing from the normal map "faked" surface. Imagine a flat polygon plane, extrude a central polygon outwards. Generate a normal map from that and apply it to a flat polygon plane. Now... when rendering the low polygon object with the normalmap I would want shadowing on itself from that "faked" extruded face.

And I want this to work in Mental Ray.

I think Brice's BRDF Shader has this, but it wouldn't work in MR so it's not really an option in this case.

ivars

I think you'll need heightmap data for that.

kodde

ivars wrote: »

I think you'll need heightmap data for that.

I was thinking about that as well. A displacement map would probably be on way around this for my grand plan.

But I am curious how NMap self shadowing works in other scenarios. I mean for example Brice's BRDF Shader has Nmap self shadowing, does this use any height data? I should get around to actually trying this out with his shader.

Brice Vandemoortele

Hi there
indeed relief mapping uses a height map and the shadowing calculation does not rely on the normal map info.
Are you looking for an alternative to ao? like a process that would give more directionality to the baking? Maybe you could take a look at IBL baking, which is more likely to give subtle shadows than procedural lights.

kodde

I was playing around with a Dome Light Setup application for Maya. I liked the results and tried baking them to textures. I found the results to resemble AO but I found this more appealing and was wondering if I could also get the Normal Map to cast shadows with the Color > Batch Bake (Mental Ray) in Maya.

Therefor the question about Self-Shadowing with Mental Ray.

Thanks for the replies.