Setting up a Z-Depth pass in V-Ray

#1

Hey,

I guess it’s kind of a basic question, but when adding a z depth pass in rendering, how do I determine the values for Depth Black and Depth White? And are there any other parameters I need to set up to get a “correct” z depth pass?

Thanks!

#2

Select your Zdepth pass in the render elements tab in the render settings. The node with all its options should then show up in the Attribute Editor. There you can tweak the black and white depth values. Remember to disable filtering there as well.

#3

Yeah but how do I determine the values for the black and white?

#4

Um, not sure what the problem is. You highlight your Zdepth pass in the render elements tab and the attribute editor will load the appropriate node with all the relevant options (including black and white depth) right there.

#5

Thanks man but when I leave the default settings as is ( black is 0 and white is 1000) I get an image that’s all white so I figured maybe there’s something wrong with those settings

#6

These two settings need to be tweaked according to your scene scale. Use the measure tool to find out the distance between your camera and the farthest object, which you want to include into your Zdepth pass - use that value for the black depth value. Now measure the distance between the camera and the closest visible object and use that for your white depth. Your Zdepth pass should now correctly display the specified areas, giving you nice gradients all across. You can swap the black and white values, if you are more comfortable working that way.

#7

You can also turn on Object Details under Display>Heads Up Display, this will show you the distance of the selected object from the camera.

If you already have shaders on everything in your scene, another good trick is to go to your render layer and set a plain black surface shader as the a material override. This way, you can get quick feedback on your zdepth pass while you tweak the settings without having to wait for the beauty pass.

#8

Okay so it really drove me crazy because no matter how hard i tried i kept getting pure black images, i was starting to think about re-installing v-ray and such…

But then i realized that when modeling the scene, my working units were set to “meters”, and apparently the values you need to plug into the z-depth pass parameters should be in centimeters… so… problem solved :slight_smile:

Many thanks guys!