Polys with Subdivision render black with VrayDirt

[RICHARD_SIMPSON]

I've got some poly objects that render solid black in my ambocc pass using VrayDirt, and it's somehow related to Vray doing the subdivisions. If I turn on Render Viewport Subdivision or add a Vray Subdivision attribute, it's solid black. If I get rid of these or use Smoothing on it instead, it renders correctly.

The normals are all correct, it looks correct in the viewport with Double Sided Lighting turned off, and the objects render correctly in all other render elements with subdivisions, but not with VrayDirt.

Any ideas why? Or how to fix it?

My workaround is applying smooth to it, but that's not a fix.

-R

[vlado]

Is it possible to post a scene for this or send it to vraymaya@chaosgroup.com? I can't reproduce this here on a simple test.

Best regards,
Vlado