Copyright Goodheart-Willcox Co., Inc. Chapter 14 Model Documentation, Analysis, and File Exchange 387 Display style: drop-down list in the Color Mapping area determine how the curvature is analyzed. The options are described as follows: • Gaussian. This is the default option. AutoCAD analyzes areas of high and low curvature in the model. The color red is assigned to areas with positive curvature. A positive Gaussian value indicates that the surface has a bowl or spherical shape. The color green is assigned to areas with zero-value curvature (fl at surface areas). Cylindrical and conical surfaces are examples of surfaces with zero-value Gaussian curvature. The color blue is assigned to areas with negative curvature. A negative Gaussian value indicates that the surface has a saddle or hyperbolic shape. The Gaussian option is suitable for general purposes and works well with swept objects. • Mean. AutoCAD analyzes the mean curvature of values along the U and V directions of the surface. This option is useful when checking for quick or sharp changes in the shape of the surface. • Max radius. AutoCAD analyzes the maximum curvature of values along the U and V directions of the surface. This option is useful for determining how fl at or curved specifi c surfaces are. • Min radius. AutoCAD analyzes the minimum curvature of values along the U and V directions of the surface. This option is useful for checking surfaces with small radius bends. The values in the text boxes at the ends of the color gradient bar in the Color Mapping area defi ne the curvature range from minimum to maximum curvature. The default values are 1.0 and –1.0. The values are used to defi ne the acceptable curvature range. AutoCAD displays the corresponding color in the color gradient bar when a curvature value is reached. Maximum values are indicated in green and minimum values are indicated in blue. The resulting display can vary depending on the range of curvature values entered. The Auto Range and Max Range buttons are used to calculate ranges of curvature values of selected objects. When the Auto Range button is picked, the calculation is based on 80% of the values in the curvature range. This can provide a starting point for setting the minimum and maximum curvature values. When the Max Range button is picked, the calculation is based on the maximum range of values. To select surfaces to analyze, pick the Select objects to analyze button in the Curvature tab if the Analysis Options dialog box is open. Otherwise, use the ANALYSISCURVATURE command. Before using this command, make sure that a 3D visual style is set current. Once you initiate the command, select the surfaces and press [Enter]. You can select one or more surfaces or solids. If needed, access the Analysis Options dialog box to set the curvature range. In Figure 14-49, a model created from a loft surface is analyzed using the Min radius option. In Figure 14-49B, the features at the end of the model are checked. In the ANALYSISCURVATURE Ribbon Surface Analysis Analysis Curvature Type ANALYSIS- CURVATURE Pick to access analysis options Figure 14-48. The Curvature tab of the Analysis Options dialog box.