■ Generating Displacement Maps 311Accessing Your Original Mesh Shape
ZBrush is a multiresolution editing tool, meaning that changes you make at the higher sub-
division levels will telegraph back down to the lowest subdivision level, somewhat changing
the shape of the original mesh. In some cases, you may want to access your original mesh
shape again; for example, you may want to generate a displacement map against the shape
built in Maya, as opposed to the somewhat different level 1 shape that will result after
sculpting in ZBrush. Here are some hints for doing this:
• To ensure that you can return to the original Maya shape in ZBrush after sculpting,
store a morph target before you begin sculpting by clicking Tool → Morph Target →^
StoreMT before you start modifying your model. After sculpting, you can use Tool →^
Morph Target → StoreMT to switch back to the original shape.
• An alternative way of doing this, which does not require storing a morph target, is
simply to reload the Maya model after sculpting as the level 1 mesh of your sculpted
model. This approach will work as long as vertex ordering has not changed (which
should be the case as long as you have not added or removed points or edges). The
morph target method is generally preferred because some programs can, on occasion,
alter the order in which they write model vertices on export, even when the model has
not changed at all.
• It is also important to note that using tools like the Pinch Brush will make changes to
the mesh that will not necessarily translate well into the maps created when setting a
DPSubPix value as opposed to those generated using Adaptive mode (these settings
will be discussed in detail later). This explains why, in many cases when using these
tools on your mesh, you’ll find it beneficial to use the slightly shape-modified level 1
mesh for your base in Maya as opposed to the original morph target.
• In any case, always apply your displacement map to the geometry you generated it from
in ZBrush. If you use the original morph target, be sure to export this mesh to Maya
for displacement.
If you find that areas that have been pinched together are creating undesirable effects in
the render, try using the Reproject Higher Subdiv button under Tool → Geometry. Reproject
Higher Subdiv will allow you to relax the underlying edges while maintaining the sharp
edges. This tool is discussed in depth in Chapter 2, “Sculpting in ZBrush.”
If your base mesh is already rigged and cannot be changed in Maya, export the ZBrush
level 1 mesh as an OBJ import into your Maya scene, and add it as a parallel blend shape
to reshape the original mesh to the level 1 form exported from ZBrush.Making 16-Bit Maps
You created a 16-bit map earlier when you created the displacement map for the GoZ export
exercise. Here we will look at the 16-bit map settings in more detail. Sixteen-bit maps carry
less information than 32 bit. They can give great results when used correctly, but it will
come down to a question of artist preference as well as pipeline requirements when deciding
whether to use 16-bit or 32-bit maps.