volume fog for Z depth

[jacksc02]

I have seen a tutorial that uses a black volume fog to render z depth maps. I have struggled with max to get a black volume fog to work.
If there is a volume fog guru out there that can help (or suggest an alternative) it would be greatly appriciated!

Thanks in advance

Chris Jackson
cj@arcad.co.nz
www.arcad.co.nz

Tutorial is here

http://www.angelfire.com/grimoireinterdit/tutorial_dof/DOF.htm[/url]

[trixian]

In case you don't want to walk down the dark path of black fog, you can alternatively:
1) Check z depth in the vray g buffer rollup.
2)render it out through the render elements dialogue (uncheck filter).
3)Add it as a file output in the effects dialogue.

[jacksc02]

trixian, I have tried to render out the z depth with vray g buffer, but where do the files get saved to?

[trixian]

To be honest I never use that procedure at all. I either use the render elements, or the file output.
When specifying your render output, the vfb gives you both the rgb output and the z-buffer in the little dropdown. But it never saved the z-buffer in my case, only the rgb image.
Maybe someone else can comment?

[vance3d]

When you use the method of checking channels in the vray g buffer channel dialog, those same channels must be selected in the setup section of the rpf or rla file you are saving.

only these formats will embed the extended channel info in the file in addition to the RGB and A channels.

Then you can access these channels in a compositing program.

Don't try to have vray render out an rpf with extended channels without checking them in the g buffer dialog or vray will crash when it tries to save the file.

V Miller