zbrush to Vray

[ndeboar]

Hey,

I'm not having any luck with getting displacment maps from zbrush to vray. I'm exporting 32bit displacments, and thought they should work fine.

Does anyone have a good workflow they can share?

Cheers!

Nick D

[jensl]

Are you using exrs? I've had the most luck with that format, although you may need to export something else and then convert to exr in photoshop. I don't use zbrush much so I forget the details.

[ndeboar]

im converting from a tif to exr in nuke, still no luck. 16bit is working fine, 32bit not having any luck.

[vlado]

Which V-Ray version are you using?

Best regards,
Vlado

[cdavis]

I had trouble from mudbox & was told to turn on the "allow negative shader color" in the misc tab to get 32 bit disp's working , & that did the trick. not sure if youve tried that yet.

Chris

[aweidenhammer]

I've never gotten 32 bit displacements out of zbrush to work. I know over quite a number of zbrush versions, they seem to keep f****ing up export in one way or another. I am able to get 16-bit to work fine though, so I suggest using that.

[MoonDoggie]

I had a thread back where I do a ZBrush "old man head" where I didn't have too many problems doing it. I believe I used 32-bit displacement map generated directly from ZBrush.

http://www.chaosgroup.com/forums/vbu...light=man+head

[ndeboar]

Im using 1.5 sp1. I'm going to try the nightly builds and see if that works.

[ndeboar]

Finally had some time to look into this.

I'm using build 13974

32bit tiffs still don't work, all the values above 1 get clipped. Converting it to an EXR fixes this, but the displacement doesn't match zbrush. I have ticked use negative color. So what is there workflow here? I thought 32bit displacements should work with out fiddling with displacement amounts/shifts?

Nick

[Metzger]

I would never put an exr into Photoshop period. Nuke it or bust. One of the most important workflows tips to keep in mind is that you want to keep model to scale when you paint your maps in zbrush. In nuke you want to have your read node clicked with RAW DATA so no gamma is applied to your file.

In maya when you layout your low res cage, make sure you measure scale in CM. Then start your zbrush painting. Export 32bit tifs and allow negative color. Also, don't use automatic UV maps. You might display great in Zbrush, but your map exports if Automatically mapped will not have enough resolution.

If you are scaling your object or do not pay attention to scale you will distance yourself from quicker results.

[ndeboar]

im doing all my exports in nuke, no color space changes, linear-linear. Havn't done any scaling. Using the properly layed out uvs from maya, not generating them in zbrush. Looks fine in mental ray, doesnt work in V-Ray. Have you got 32 bit displacements working? Would you care to post an example zbrush/maya scene?

[vlado]

Which file format are you using for the 32-bit displacement?

Best regards,
Vlado

[Metzger]

I was trying a test using Zbrush 4 and it looks as if they changed something. I tried both build 11965, along with a newer build and I couldn't get a 32bit tiff from Zbrush 4.0 to render correctly.

I had success when using Vray for displacement from maps that came from Zbrush 3.5.

[ndeboar]

I'm using Zbrush 4 too. Tifs get clamped to 1, and exrs dont match z-brush.

Cool. Vlado, is this a "bug", can it be looked into? Or at least a clear tutorial for getting things from z-brush to vray.

[Metzger]

I think it's possible that Zbrush 4.0 changed things up a bit. Would be nice to hear from someone else though.