Vector displacement in Modo by Xuan Prada

Another quick entry with my tips&tricks for Modo.
This time I’m going to write about setting up Mudbox’s vector displacements in Modo.

  • Check your displacement in Mudbox and clean your layer stack as much as you can. This will make faster the extraction process.
  • The extraction process is very simple. Just select your low and high resolution meshes.
  • Set the vector space to Absolute if you asset is a static element, like props or environments.
  • Set the vector space to Relative if your asset will be deformed. Like characters.
  • Always use 32 bit images.
  • As I said export the maps using EXR 32 bits.
  • Before moving to Modo or any other 3D package, check your maps in Nuke.
  • Once in Modo, select your asset and go to the geometry options.
  • Check Linear UVs and set the render subdivision level.
  • Assign a new shader to your asset.
  • Add a new texture layer with your vector displacement map.
  • Set it up ass Displacement Effect.
  • Set the low and high value to 0 and 100.
  • You will see a displacement preview in viewport.
  • Set the gamma to 1.0 Remember that 32bit images shouldn’t be gamma corrected using Linear Workflow.
  • In the shader options set the Displacement Distance to 1m this should give you the same result than Mudbox.
  • In the render options you can control the displacement rate, which is your displacement quality more or less.
  • 1.0 is fine, play with that. Lower values will give you sharper results but will need more time to render.
  • Finally render a quick test to see if everything looks as expected.

Mudbox and UDIMs by Xuan Prada

When you’re going to texture an asset which already have a displacement map, probably you’ll want to apply that displacement to your mesh before start the painting process.

In my pipeline, I usually apply the displacement map in Mudbox and then I export the high resolution mesh to Mari.

The problem here is that Mudbox doesn’t allow you to work with displacement maps and multiple UV shells.

I tried below to find a solution for this problem.

  • Check your UV mapping in Maya.
  • I’m using these simple displacement maps here.
  • One map for each UV shell.
  • Export as .Obj
  • Open in Mudbox and subdivide.
  • Go to maps -> sculpt model using displacement map.
  • Select your mesh and your displacement map.

As you’ll realize, Mudbox doesn’t allow you to choose different maps for each UV shell which means that Mudbox will be able only to sculpt using the displacement map for U0-1 V1-0 coordinates. Big problem.

The way which I’ve found to solve this problem is:

  • Go back to Maya.
  • Select your mesh and open de UV Texture Editor.
  • Select one of the UV shells which is outside of the default U0-1 V1-0 range.
  • Open the script editor and type -> polyEditUV -u -1 -v 0 ;
  • You’ll notice that the second UV shell is placed in the default UV shell but was moved 1 exact position. Then your displacement texture  will match perfectly.
  • Export again as .obj
  • Now you’ll can use your displacement map in Mudbox without problem.
  • Repeat the process for each UV shell.
  • Commands to move UV shells 1 exact position.

Move left -> polyEditUV -u -1 -v 0 ;

Move right -> polyEditUV -u 1 -v 0 ;

Move up -> polyEditUV -u 0 -v 1 ;

Move down -> polyEditUV -u 0 -v -1 ;