Hey!
Have a strange problem. I have a workaround but maybe it is a bug…
Scenesetup:
Interior scene (bath); physical camera with 27mm focal lengt (FOV: 67deg), nothing special.
Set up VRayZDepth (use cameraboundaries) to comp a DOF in post, but in the saved EXR the gradient of the depth is not planar as it should - it has a spherical projection/orientation to the world (?) space. The saved EXR G-Buffer-Channel (Depth) to compare the images seems correct. See attached image (left side VRayZDepth, right side G-Buffer-Channel). While using the VRayZDepth in comp I have a curved sharpness level (see the second screenshot attached)
Basically it is not a big deal but a bit strange and i’m not sure if the problem is the software or sitting in front of it.. 
Hey,
If no answer then it is probably obvious that the problem sits in front of the computer 
Does anyone have a hint?!
Cheers!
Hi,
The following behavior is expected. V-Ray ZDepth is measuring the distance from the camera itself. In scanline for example, it is measuring the distance from the camera plane.
There is a workaround for this. You can use VRaySamplerInfo render element. Set the type to point and coordinate system to Camera. Then you have to set a value of -1.0 for the point multiplier. This is not available using the UI, but you can set using MAXscript..
maxscript. ((maxOps.GetCurRenderElementMgr()).getrenderelement 0).point_multiplier=-1.0 ( when the 0 is the render element index ).
Save the render element as EXR and open it in a compositing software like Nuke. You have to use the blue channel and maybe some negative gain is required.
http://ftp.chaosgroup.com/support/screenshots/2019-02-21\_15-51-06.gif
Best Regards,
Martin Minev
Chaos Group Support
