Tentacles – Dodo, Maya, IBL & Vector Displacement

Dodo Master Feather System

I succeeded in the proof of concept for using geometry scales on the outerside of the tentacle  using a great Maya script called Dodo Master Feather System made by Semir Saleh.
The script is a joy to use and works very well, here is the proof of concept video.

The scales will eventually be scaled down and multiplied to achieve the smooth effect, as this is only a test i didn’t want to waste too much time on processing.


  • Using nurbs patches I manually covered the Poly geometry ( which has been rigged and skined, doing this avoids breaking things 🙂 )
  • Created a wrap deformer to the poly Geo
  • Tested the rig to make sure everything was OK
  • Modelled a single polygon scale, making sure to create the UV as well
  • Applied Dodo Master to the Nurbs patch and adjusted settings as needed.

Mudbox to Maya IBL render

Next was to make sure I could generate various maps from the hi-res mudbox sculpt; textures were 2k and 4k in size and rendered with a HDR IBL

  • Diffuse
  • Ambient Occlusion
  • Specular
  • Gloss ( spec fall off  )
  • Bump
  • Vector Displacement

Raw render with IBL background
Everything but the vector displacement map was pretty easy to hook up to a Blinn shader network below.

Shader Network for mudbox to maya

Why vector displacement

  • A lot faster to render ( by a factor of 2 – 3 )
  • Not just limited to up and down displacement, which would provide a smoother deform.
  • A ‘lot’ easier and faster to generate from mudbox.

The problem is that Mental Ray 2011 doesn’t support vector displacement maps! Seems crazy that something so good should be left out…
But thankfully to another great script by Wayne Robson – vector displace shader DL I was able to hook up and use the vector displacement map no problems.


  • when extracting the vector displacement map from mudbox use either world, or object space tangents.
  • add a mental ray subdivision approximate to the geomtry
  • Connect Wayne’s shader to the Shading Group’s displacement input.

That’s it! Previously I have had major headaches with extracting and rendering standard displacement maps, but using VDM made things so much easier. The still render took only 1 min with IBL and Final Gather switched on to 256. Optimising pipelines FTW.

So for a little fun I comped the render in photoshop for some monster action! Cheesy I know, but what the heck 🙂

Quick Comp
click for full size horror!

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