Copyright Goodheart-Willcox Co., Inc. Chapter 9 Mesh Modeling 215 When creating mesh primitives, set the mesh tessellation divisions before creating a mesh primitive shape. Setting the proper values for the mesh tessellation divisions ensures the model has enough faces, edges, and vertices for editing. The default tessel- lation divisions are listed in the Mesh Primitive Options dialog box, which is discussed in the next section. Within the tessellation division, the face consists of structures known as facets. See Figure 9-2B. The facets create a grid pattern that is related to the smoothness of the mesh. As the smoothness level of the mesh object increases, the facets increase in number, resulting in a smoother, more rounded surface. As the smoothness level decreases, the facets decrease in number, resulting in a rougher, less rounded surface. You can change the default smoothness of a mesh primitive by entering the Settings option of the MESH command, which is discussed in the next section. Figure 9-3 shows an example of a box mesh primitive created using the default tessellation divisions. The default settings create a box with no smoothness, length divisions of three, width divisions of three, and height divisions of three. NOTE NOTE Any mesh object or subobject that has a level of smoothness of 1 or higher can be refi ned by converting facets to editable faces. Refi ning a mesh is discussed later in this chapter. You can also adjust the appearance of the facets by setting the VSLIGHTINGQUALITY system variable. Graphic card and monitor display may affect visibility. Facets A B Tessellation lines One tessellation division Edge of face Figure 9-2. A—Tessellation divisions are key to mesh modeling. They define the smoothness of the mesh model. B—Facets on a mesh face. A B Figure 9-3. This box mesh primitive is drawn with the default settings. A—Displayed with the 2D Wireframe visual style current. B—After the HIDE command is used.