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Chapter 10: Accessing Subobjects and Using Modeling Helpers

FIGURE 10.1
The Show Normals option shows the normal vectors for each face in a Plane, a Box, and a Sphere.

Tutorial: Cleaning up imported meshes
Many 3D formats are mesh-based, and importing mesh objects sometimes can create problems. By collaps-
ing an imported model to an Editable Mesh, you can take advantage of several of the editable mesh features
to clean up these problems.

Cross-Ref
The Modifier menu includes two modifiers that you can use to work with normals. The Normals and Edit Normals
modifiers are covered in Chapter 26, “Deforming Surfaces and Using the Mesh Modifiers.” n
Figure 10.2 shows a model that was exported from Poser using the 3ds format. Notice that the model’s
waist is black. It appears this way because I’ve turned off the Backface Cull option in the Object Properties
dialog box. If it were turned on, his waist would be invisible. The problem here is that the normals for this
object are pointing in the wrong direction. This problem is common for imported meshes, and you’ll fix it
in this tutorial.
To fix the normals on an imported mesh model, follow these steps:
1. Open the Hailing taxi man with incorrect normals.max file from the Chap 10 directory on
the DVD.
2. Select the problem object—the waist on the right mesh. Open the object hierarchy by clicking the
plus sign to the left of the Editable Mesh object in the Modifier Stack, and then select Element
subobject mode.
3. In the Selection rollout, select the Show Normals option and set the Scale value to a small number
such as 0.1.
The normals are now visible. Notice that some of them point outward and some of them point
inward.
4. With the element subobject still selected, click the Unify button in the Surface Properties rollout
and then click the Flip button until all normals are pointing outward.
This problem is fixed, and the waist object is now a visible part of the mesh. The fixed mesh on the right
looks just like the original mesh on the left without the ugly black shorts, as shown in Figure 10.2.

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