Split render channels output of G-Buffer channels not working?

[dans]

If I use a file format (e.g. RPF) or a render effect that requests some G-Buffer channels from the renderer then V-Ray will provide those in the 3ds Max VFB. If I now enable the Split render channels output of the V-Ray framebuffer then some of there G-Buffer channels are also written as separate render channels to disk. However these files (Node_ID, Material_ID, Material_color, Material_transparency, Sub-pixel_weight, Unclamped_color, UV_Coords, Velocity, Z-Depth_(max)) are always all 100% black. I tried TGA, TIF, EXR and PNG here using 3ds Max 2012 / 64-bit and V-Ray 2.10.01.

Render Channels Type	Split Channels Output	SDK - PixelBuffer Access
Render RGB & Alpha	OK	OK
V-Ray Render Elements	OK	OK
V-Ray Lens Effects	OK	OK
G-Buffer Channels	always black	Not working?

So I don't know if the bug is that these are black or if these channels shouldn't be written to disk in the first place.

Best Regards,
Daniel Schmidt

[vlado]

The "split render channels" option does not work with the G-Buffer and it was never intended to work (the V-Ray VFB itself does not store the sub-pixel information).

If you want to write sub-pixel information, you'll have to intercept the renderer output, similar to how this is done in the VRayStereoscopic plugin for the shademap. The source code for the VRayStereoscopic helper is included with the V-Ray SDK.

Best regards,
Vlado

[dans]

I just noticed these channels while using the Pixelbuffer interface (which works great) and will snow kip them during PSD export.

However VRay shouldn't write these channels to disk. As soon as any G-buffer channel is needed by some effect and the split channels option is used these files get written and waste space.

Thank you,
Daniel

[vlado]

However VRay shouldn't write these channels to disk. As soon as any G-buffer channel is needed by some effect and the split channels option is used these files get written and waste space.

Yes, this is true... will see if we can do something about it.

Best regards,
Vlado