Topics are collections of feature classes, and are used to organize data elements in the AutoCAD Map 3D Data Model pane. Topics do not imply any relationship between the feature classes contained within them.
The following line creates a “Pipe” topic, which is used to contain all the pipe-related feature classes:
Topic pipeTopic = AddTopic("Pipe", "Pipe Related Classes");
Topics can also contain other topics to create a hierarchical data structure. The following line creates a “Special” topic, which is located under the parent “Pipe” topic:
// Get the name string from a resource file.
AddTopic("Special", "Pipe Related Classes", pipeTopic);
For more information about feature classes, see Feature Classes.