Copyright Goodheart-Willcox Co., Inc. 428 AutoCAD and Its Applications—Advanced Lighting The Highlight intensity property controls the VSFACEHIGHLIGHT system variable. This property determines the size of the highlight on faces to which no material is assigned. A small highlight on an object makes it look smooth and hard. A large high- light on an object makes it look rough or soft. The initial value is 30 or –30 the value can range from –100 to 100. The higher the setting is above 0, the larger the highlight. Settings below 0 set the value, but turn off the effect. To quickly turn the effect on or off, pick the Highlight intensity button on the Lighting category title bar. Refer to Figure 16-10. This changes the value from negative to positive or vice versa. This prop- erty cannot be changed if the Face style property is set to None. The Shadow display property controls the VSSHADOWS system variable. This property controls if and how shadows are cast when the visual style is set current. The options have slightly different names, but are the same as those available by selecting a button in the shadows fl yout in the Lights panel on the Visualize tab of the ribbon. Remember, however, a setting made using the ribbon is temporary and does not rede- fi ne the visual style. If the property is set to Ground shadow, objects cast shadows on the ground, but not onto other objects. The “ground” is the XY plane of the WCS. The Mapped Object shadows setting, which corresponds to the Full Shadows button on the ribbon, only works if lights have been placed in the scene and hardware acceleration is enabled. Environment Settings The Backgrounds property controls the VSBACKGROUNDS system variable. This property determines whether the preselected background is displayed in the view- port. Backgrounds can be assigned to a view when a named view is created or edited. After the view is created, restore the view to display the background. Edge Settings Properties in the Edge Settings category determine the appearance of model edges. This category includes the Occluded Edges, Intersection Edges, Silhouette Edges, and Edge Modifiers subcategories. Refer to Figure 16-5. The Show property controls the VSEDGES system variable. This property deter- mines how edges on solid objects are represented when the visual style is set current. The options are the same as those available by selecting a button in the edge fl yout in the Visual Styles panel on the Visualize tab of the ribbon. The settings of Isolines and Facet Edges determine how edges and curved surfaces are displayed on a 3D model. Setting this property to None turns off isolines and facets and displays no edges. If the Face style property is set to None, the Show property cannot be set to None. The Color property in the Edge Settings category controls the VSEDGECOLOR system variable. This property determines the color of all edges on objects in the drawing. It is disabled when the Show property is set to None. The Number of lines and Always on top properties are displayed when the Show property is set to Isolines. The Number of lines property controls the ISOLINES system variable. The Always on top property controls the VSISOONTOP system variable. This property determines if isolines are displayed when the model is shaded or hidden. When set to Yes, all edges are displayed, even if they are physically hidden from view. Additional edge settings are available in the Edge Settings category when the Show property is set to Isolines or Facet Edges. These settings are available in the Occluded Edges, Intersection Edges, and Edge Modifiers subcategories. The settings in the Silhouette Edges subcategory are available regardless of the Show property setting. The settings in the subcategories are discussed as follows. VSSHADOWS Ribbon Visualize Lights Shadows Off Ground Shadows Full Shadows Type VSSHADOWS VSEDGES Ribbon Visualize Visual Styles No Edges Isolines Facet Edges Type VSEDGES