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Exporting Displacement and Normal Maps

ZBrush Usage Questions
#1

I have a rather good idea of the theory of combining displacement and normal maps so that in Maya you can have a low-poly mesh and yet still reproduce the high-poly details you sculpted in zBrush.

My understanding is that you create a displacement map from the first subdivision level until you reach a level where the changes in silhouette are minute enough that they cease to matter. From that point forward, you would use a normal map to reproduce the high frequency detail.

However, when you go to export displacement maps in zBrush (using the Multi-Map Exporter Plug-In, for example) you only specify the subdivision level where you want the map created for.

So, for instance, if you had five subdivision levels, and wanted to export the first level for use in Maya, you would create a displacement map at subdivision level one. My question is this: wouldn’t that create a displacement map that contains the details all the way up to subdivision level five?

Is there a way to specify that you only want a displacement map between levels one and three, and that you want to create a normal map for levels four and five?

I’m obviously still a bit confused about how map exporting works with all the subdivision levels, and any clarification would be much appreciated.

#2

ZBrush will always use the detail from the highest subdivision level when creating the map. I can’t comment on the merits of using displacement maps and normal maps together but you could generate them within ZBrush like this:

  1. Back up your model.
  2. Set the subdivision level that you want to generate your normal map from and create the normal map.
  3. Set the subdivision level that you want to use as the basis for your displacement map. Press Tool>Geometry>Del Higher to get rid of the higher subdivision levels. They then won’t be used in the map.
  4. Set to the lowest subdivision level and create the displacement map.
#3

Thank you. That clarifies a lot. I was afraid I was missing something.

#4

I should add that if you have HD Geometry and wish it to be included in either a displacement or normal map, the SculptHD Subdiv level should be at the highest level and the ordinary subdivision level at the lowest.