VRayAO renderpass background

[Garryclarke]

Hi,

I want to render a VRayAO render pass and composite on top of the RGB pass in the frame buffer.

But the renderpass renders the background as black so that when I comp it on top it turns my background black (I've set a coloured background in the Environment dialog)

The help says 'The background is calculated with unoccluded color by design. You can use compositing with the New V-Ray Frame Buffer (VFB)' Surely the 'unoccluded color' is white? but it renders black.

So I can't use the AO pass to comp on anything if there is an empty background in the shot.

Am I doing something wrong?

I'm using VRay 5

[Garryclarke]

Ahh I think I've tracked it down - I'm using a VRaySphereFade and it gives the AO pass a black background outside of the sphere.

Any workarounds?

[hermit.crab]

Maybe enable the "Affect alpha" of the SphereFade, so as to use it as a mask?