ZDepth render element is writing 1 instead of INF on non clamped VrayZDepth

[tdugard]

Hello, since we use Vray 5 we are facing a very annoying issue, we use a non clamped ZDepth render element to do the DOF in comp in a real world scale to match the 3d one. So we are entering :
ZDepth Min = 0
ZDepth Max = 1
Clamp Zdepth : False
Invert Zdepth = False
So we can have a perfect zdepth value of object position in scene.

But when we have no object, the zdepth render element write 1 instead of inf. that is really annoying because its like the far background is at 1 unit instead of infinity so it mess up the dof.
Plus when we have an object at 1 unit from cam, its value is the same as the far background.

Here is a scene i've rendered to show the issue, the "object at 1" is approx at 1 unit from camera and in the zdepth pass it has some shareds value with the background.

Another issue is the Matte objet that are visibile in the depth pass, i've unchecked the Gen render elements in the Vray Properties so it output 0.
I think the best option is the have the same INF value or 0 for matte object and background because their alpha in the beauty pass is 0 for both (or when clamp is off = INF and clamp is on Min or Max value depends is Zdepth is inverted or not)

In maya there is a Force Black At Infinity option to at least put 0 at inifinty.

For the moment the Zdepth pass is unusable.

I know i can use the VraySamplerInfo but when you have matte object the Gen render elements = False does not work in the position pass (the object still visible) so when you use some render layer management pipeline tools (rendering characters separated from env) you can't use it because mate object are polluting the position pass

Here i've made some teak in nuke to isolate pixel that have z value = 1 in nuke to show the issue.

What can we do ?

Thanks

[hermit.crab]

Thanks for the report. I've logged an improvement request (internal bug-tracker id: VMAX-13639) for the "Froce black at infinity" option in 3ds Max.

[tdugard]

Thanks but it should ever be at 1 like it is right now for those obvious reasons i have mentioned before. Even 0 is a workaround but not correct.

For me the correct behaviour is INF when non clamped (it was the case before) and max depth when clamped. No really need a force black at infinity (but it can be a good option for those software which can't manage INF pixels).

Do you know that its something we can have in vray 5 in a nightly build ?

[hermit.crab]

Do you know that its something we can have in vray 5 in a nightly build ?

Can't really say. I'll notify you if there's any movement.

[tdugard]

Hello, have you got some news about this issue ?

[hermit.crab]

No movement yet, I'm afraid.

EDIT: I may have been confused the first time I troubleshot this issue. It seems that the issue lies within the Depth Clamping (it behaves as always on). In theory, simply disabling the Depth Clamping, Force Black at Infinity = off and Depth black = 0 should yield inf values. Will talk with the devs again.