vrayMTL with viewport 2.0 and screen space ambient occlusion

[djx]

This is probably a maya problem, but I thought I would ask here in the hope that someone can help. I'm trying to set up some quick viewport renders using the ogsRender (like viewport 2.0). The vray MTL seems to render as expected for normal shading.

Here's the problem. If I put a card in front of my other objects and assign to the card a vrayMtl that is self-illumination and opacity mapped, it all works as I'd expect until I turn on screen based ambient occlusion. The occlusion is masked by the card, even in the transparent areas. I suppose this is probably a limitation of screen based ambient occlusion.

But if I swap the card's shader from the vrayMtl to a maya surfaceShader with the same color and transparency maps, then I get the opposite effect. Now the occlusion is on top of everything, including the card (which just looks weird).

I was kind of hoping that there might be a workaround, or even a flag I missed, because I'd really like to have the occlusion masked correctly by the card.

Does anybody have a suggestion?

thanks
David

[ivaylo.ivanov]

I tried with materials like blinn and lambert, but the problem looks the same as with VRayMtl. The effect is because the SSAO shade according the normal of the object and probably do not work with transparency. You can try to enable backface culling in the viewport and turn on double sided of the material. This looks to work somewhat well with VRayMtl.

[djx]

Thanks for your suggestion. Are you saying that with backFaceCulling and doubleSided you can see the SSAO through a transparent surface? Because, so far I cant. I'll try on a better graphics card, with a later version of vray tomorrow.

cheers
David

[ivaylo.ivanov]

No, you will not see the SSAO, but in this way it will be more consistent from the two sides . Proper SSAO is probably imposible.

[djx]

Yes I'll just have to live with it. Thanks for the other tips though. And I must add, its really nice that the vrayMtl works in viewport2.0.

cheers
David