The AcGiEdgeData and AcGiFaceData classes allow you to specify the visibility type for the edges or faces in a mesh or shell primitive. There must be exactly one visibility entry in the array for each edge or face in the primitive. Passing in an array of an incorrect size causes unpredictable results.
The visibility type for edges and faces, AcGiVisibility, can have one of the following values:
- kAcGiInvisible
- kAcGiVisible
- kAcGiSilhouette
If the surface is not curved, or the edge is not required for viewing purposes, specify kAcGiInvisible. For hard edges of a surface or visible creases, specify kAcGiVisible. For edges or faces that you can see from certain viewpoints, specify kAcGiSilhouette. The silhouette visibility type is recognized only by the HIDE command; otherwise, it is interpreted as kAcGiVisible.
For example, in the solid cylinder shown below, the edges that form the rims of the cylinder are visible edges. The latitudinal edges are invisible edges, since they are never used for viewing purposes. The longitudinal edges are silhouette edges, since they are used when the cylinder is viewed from certain angles.
