Matte/visibility problem

[ruud3dv]

In this scene the camera is positioned outside the room and i've set the properties of the window and wall right in front of the camera to 'Not visible to camera'.

I've completely disabled GI and environment lighting for testing, but the 'invisible objects' are still partly visible, it looks like some internal backfaces are picking up shadows.

I've tried several combinations in Vray object properties:
- Enable/disable matte object
- With 0, -1 and 1 as alpha contribution
- Shadows and alpha ticked and unticked

But even when not set as Matte, and alpha contribution set to 1 or 0 it still creates an alpha image as attached, and 'pollutes' the rendered image with dark areas.

Does anyone know a solution?

[ruud3dv]

It turns out to be a glitch/bug with coplanar faces. The outside of the windowframe is in the same plane as the inside of the wall-opening.
There is also an outerwall solid (brick) and an innerwall solid (white plaster) that touch faces inside the wall. Removing these coplanar faces solved the problem.

But in my opinion, when 'Not visible to camera' is checked, coplanar faces of those invisible object shouldn't result in visible noise in the image/alpha.

[olivervfx]

I have the same problem, but with Vray for maya.

Vlado any solution ?


O.