Depth maps with Vray?

Stinkie · 5 Oct 2009, 20:01

Any of you geniuses know how to render a usable depth map with Vray?

solo · 5 Oct 2009, 20:26

Tom, what exactly do you need the depth map for?

Post editing?

thomthom · 5 Oct 2009, 20:30

When you give the far and near values - you always have to give them in inches. Inches is the internal units of SU and VfSU deal with this regardless of your model settings.

Ecuadorian · 5 Oct 2009, 20:39

@thomthom said:

Inches is the internal units of SU.

Aaaaargh!... Is there any way I can "unread" this? Tell me it isn't so!

Stinkie · 5 Oct 2009, 20:43

@solo said:

Tom, what exactly do you need the depth map for?

Post editing?

Yeah ... PP DOF.

Ecuadorian pointed out to me I could render one with another app, and that's what I've done so far, but ... I'd really like to know. I've been wondering about this ever since I got my Vray license, and I'd like to get rid of that nagging feeling.

Geeky, I know.

@thomthom said:

When you give the far and near values - you always have to give them in inches. Inches is the internal units of SU and VfSU deal with this regardless of your model settings.

You sure? I remember reading somewhere it should be scene units (according to Damien Alomar).

solo · 5 Oct 2009, 20:45

This may help.

http://twilightrender.com/phpBB3/viewtopic.php?f=18&t=511

Stinkie · 5 Oct 2009, 20:53

Thanks for that, Pete, but a third-party solution is not what I had in mind. One cannot keep installing software. And certainly not to do things that, in principle, one's rather expensive render engines should be able to do all by themselves.

remus · 5 Oct 2009, 21:21

I dont know if you can write shaders for vray, but a rather clever chap on the indigo wrote a shader for indigo that basically produces a depth map, might be worth a try or try and wrangle someone else in to trying it.

solo · 5 Oct 2009, 21:22

Vray does render depth maps, reflection maps, and even alpha maps.

thomthom · 5 Oct 2009, 21:38

@solo said:

Vray does render depth maps, reflection maps, and even alpha maps.

And they are found under the VFB Channel section in the Options.

@unknownuser said:

You sure? I remember reading somewhere it should be scene units (according to Damien Alomar).

Yes, 100% sure. I know Damien claimed otherwise previously, but I corrected him on this. I'm guessing he's been using inches when modelling so he didn't notice it.
Example: no matter what model unit you have, a displacement map with a multiplier of 10, 100% white will give a 10" displacement.
When you use DOF, the override focal distance is only focusing right if you specify the distance in inches.
If you apply a bump map to a material with no diffuse texture, plain colour in SU, the bumpmap will be sized to 1"x1" if you have the UV repeat values to the default 1.0

thomthom · 5 Oct 2009, 21:50

Here's a visual example I poster in another thread: http://forums.sketchucation.com/viewtopic.php?f=322&t=18202&st=0&sk=t&sd=a&start=15#p148737

Stinkie · 6 Oct 2009, 07:19

Thanks for the info, Thom. Let's see if can get a decent depth map out of Vray today.

Stinkie · 7 Oct 2009, 08:15

In case anyone's wondering: Thomthom's absolutely right. Inches it is.

Ecuadorian · 7 Oct 2009, 08:49

Google, why didn't you tell me?

kwistenbiebel · 7 Oct 2009, 09:39

When I need depth in my render I usually add the 'depth map' option in the framebuffer section of the render section and apply it in Photosoup.
It might be a bit too dirty for your puristic renders, but it can get the job done quite fast and easy.

Rendering real camera DOF is way more tedious (Asgvis should fix that inches bug by the way) and even then you really need to set your QMC values and color mapping values well to get nice grades in the depth. Not easy...