Copyright Goodheart-Willcox Co., Inc. 386 AutoCAD and Its Applications—Advanced Before using zebra analysis, make sure a 3D visual style is set current. Then, initiate the ANALYSISZEBRA command and select the model surfaces to analyze. You can select one or more surfaces or solids. Press [Enter] after selecting the surfaces. In Figure 14-47, the three surfaces of the air duct are selected. The top and bottom surfaces of the model are loft surfaces. The center surface is a blend surface. In this part, smooth fl ow design is important. Notice the fl ow of the zebra stripes in Figure 14-47B. The stripes touch but do not align consistently. In this version of the model, the start and end continuity of the blend surface are both set to G0 (positional continuity). In Figure 14-47C, changing the continuity to G2 (curvature) creates a smoother fl ow between the surfaces. To turn off the zebra striping display, use the ANALYSISZEBRA command. Select the Turn off option. You can also select Analysis Options from the Analysis panel in the Surface tab of the ribbon to display the Analysis Options dialog box. In the Zebra tab, pick the Clear Zebra Analysis button to remove zebra striping. The Zebra tab contains options for setting the stripe display, the stripe direction, and the colors and thick- ness used for the zebra striping. This dialog box is also used to set options for surface curvature analysis and draft analysis, as discussed in the next sections. Surface Curvature Analysis Once a model is designed, it is then analyzed to confi rm the quality of the design before the actual part is manufactured. When working with models containing curved surfaces, you design with the intent that the model stays within specifi c curvature ranges for manufacturing purposes. If you design a model that falls outside specifi c design criteria, problems occur and the model cannot be manufactured. Surface curvature analysis assists in determining the overall smoothness of a 3D model design. In AutoCAD, surface curvature analysis is performed with the ANALYSISCURVATURE command. When using this command, AutoCAD applies a color gradient to the surfaces of the model. This is known as color mapping. The model is then graphi- cally analyzed. Different gradient colors indicate areas of high and low curvature and abrupt changes in curvature. When you use the ANALYSISCURVATURE command, AutoCAD uses the settings specifi ed in the Curvature tab of the Analysis Options dialog box, Figure 14-48. To display this dialog box, use the ANALYSISOPTIONS command. The options in the ANALYSISZEBRA Ribbon Surface Analysis Analysis Zebra Type ANALYSISZEBRA A B C Loft surface Loft surface Blend surface Figure 14-47. Zebra analysis. A—The original air duct model consists of two loft surfaces connected by a blend surface. B—The three surfaces are selected with the ANALYSISZEBRA command. Notice that the zebra stripes do not line up. In this version of the model, the start and end surface continuity of the blend surface are both set to G0. C—Adjusting the start and end surface continuity of the blend surface to G2 produces smoother continuity. ANALYSISOPTIONS Ribbon Surface Analysis Analysis Options Type ANALYSISOPTIONS