V-Ray Ptex Normal Displacement

Disney’s Ptex technology means that 3D artists should never have to spend endless hours on UV-map our models for painting/texturing. Autodesk Mudbox 2012 and V-Ray 2.0 for Maya has Ptex built in, so we can already start using this amazing technology. One thing is to get ptex textures painted and rendered, but another is to get normal displacement working. I had some troubles with this, and with the help from the Chaosgroup forum’s and their support guy Vasil, I managed to get it working.

Here’s how to do it:

1. Import your model into Mudbox, sculpt it however you want. Once you’re finished, go to Mesh>Ptex Setup and turn your model into a Ptex model.

2. Export your low-level mesh (level 0 or 1, or whichever you want) as an obj or fbx

3. Go to Maps>Export Texture Maps> New Operation and select Displacement Map

4. Set your target model to the level of your low-level mesh (the one you exported)

5. Set your Source model to the highest level of your sculpting

6. Use either ray casting or sub-division

7. Set your output to a 32-bit Ptex file with either Good or High quality

8. Open Maya and import your low-level mesh

9. Apply a V-Ray Material to your mesh

10. Open your Hypershade and add a Ptex node, and connect it to the VRayMtl through the displacement channel.

11. Set your cache size to a reasonable size. This usually depends on the size of your ptex file

12. Select your mesh, then go to your Attributes Editor, select the shape node and turn on Attributes>V-Ray>Displacement Control

13. Choose Normal Displacement, turn on Keep Continuity and change Displacement Bounds to Explicit

14. Click on the black color square (Minimum Value) and set these values in the HSV areas: H=0 S=0 V=-5 . Then click on the white color square (Maximum Value) and set it to this value: H=0 S=0 V=15. These are arbitrary values, so they can be adjusted to your specific value. You could always just set them to -100 (min) and 100 (max).

15. There you go, render and all should be well!

It’s amazing how well Ptex works with V-Ray and Maya. This will shave of hours and hours off your production time!

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7 thoughts on “V-Ray Ptex Normal Displacement

  1. mom

    Fantastic tutorial — the only thing I don’t get is how to change your cache size? What cache are you referring to? Thanks!

    Reply
  2. mom

    Doh, its under the VrayPtex node. But, I still am yet to get this to work. I have followed every step but the subdivs are not showing up at render time. Do I need to set v-ray subdivisions on via the extra attributes like you do on the other (non-ptex) tutorial on your site? Thanks!

    Reply
    1. Bard Post author

      glad to hear you found the cache size.
      yeah, i don’t think you actually need to add the sub-divisions via the extra attributes, but you could try it to see if it works…

      Reply
  3. Grinder

    The process seems buggy and is not working nicely at all. You have to play a lot with V in minimum and maximum value, to have something similar to real sculpt. It seems that vray is ready for ptex with color information, but not ready for efficient ptex displacement at all.
    Thank you for you tutorial anyway

    Reply

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