■ Applying Bump Maps in Maya 325Gain to increase the level of displacement, we can dial into the right settings. The render scene
file for this test head is available on the DVD. Simply open the scene file in Maya and render.
Applying Bump Maps in Maya
In most cases, you will want fine details on your mesh such as pores and small wrinkles. You
can add these into the geometry itself, and ultimately the displacement map, but that’s not
always the most efficient approach. With some preplanning, the finer details can be added
in a bump map and rendered over the displacement in mental ray. This takes a huge load off
the renderer since you don’t have to subdivide nearly as high to get lower-frequency forms
to appear. A good rule of thumb is if your detail will change the silhouette of the model,
displace it. If it is not visible in the profile, add it as a bump map detail instead. ZBrush has a
great tool for making bump maps in the Bump Viewer material. For more information on the
Bump Viewer material, see Chapter 4, “ZBrush for Detailing.” It is also possible to load your
displacement map into the bump channel.
You can also generate a bump map for your finer details in ZBrush by simply extract-
ing a displacement map from a higher subdivision level than 1. On a five-division mesh, try
extracting a displacement from level 3 and using this as your bump map.
- To apply your bump map in Maya, open the Attribute Editor for the material on your
mesh. Here you’ll see a bump mapping slot. Click the check box to the right of the
attribute name in the Attribute Editor and select File from the pop-up window. This
will create a bump2D node. You will see some options in the Attribute Editor for the
bump2D node. Bump Depth is the “volume” control for the level of the bump effect in
rendering. The initial value of 1 is usually too high, so start testing with a value of 0.5.
Render and adjust the Bump Depth value accordingly until you get a satisfactory result.
Figure 9.43 The file node name can
be found at the top of the Attribute
Editor. This node is named file2.
Figure 9.44 Pixologic test head rendered in Maya