Zdepth noise in transparent areas

[GrahamMac]

Using Max design 2012 x64 (win 7) with Vray 2.20.01

The Vrayzdepth pass, is being displayed with heavy noise in the alpha zero areas of the render in the Vray frame buffer:



If I change the image sampler from Adaptive DMC to adaptive subdivision the noise becomes limited to just the edges of the object:



If I change to fixed (subdivs: 1) the noise vanishes completely.
It seems that the noise only appears wherever there is more than 1 subdiv of image sampling, in areas of alpha zero.

I have tried to recreate this anomaly in a fresh max scene without success.
Note: this issue is only seen in the Vray frame buffer. The files saved from the render pass are perfect.

Has anyone else encountered this?

Cheers

[svetlozar.draganov]

Could you please send this scene to vray@chaosgroup.com to investigate what cause this issue !

[GrahamMac]

Thanks Svetlozar,

Scene sent!

[GrahamMac]

Chaos group technical support replied and solved this issue very promptly (as always ) so I’d better update this thread with the solution in case anyone is having the same issue.

In the Vray frame buffer there is a little dual mode button sitting second in from the bottom left. I had it switched to “view clamped colours” mode without realising its alternative mode of “force colour clamping”. When set to the latter and activated, it solved the noise issue.