Hi Peter,
I would say, stay at the RTShape level. Trachel objects are for the low level stuff. For example a
TRArcShape defines an arc based on the geometric property and with RTShapes you visualize a model
by mapping its attributes to geometric values for the visible (trachel ) shapes.
An UML class diagram is a rectangle with three segments (or three boxes). The mapping from class attributes
to the class diagram would happen on with RTShape/element/builder...., so you would need something on that level anyway.
Sure you can define a UML-Trachel shape as one geometric object. But I would only choose this
way if the object is somehow "static" and "closed".If you want to change the object(model) through the
visible representation or connect parts of it with other elements, then every single element of the
UML-diagram (class label, class vars, class methods) should be accessible on the RT-Level.
I wouldn't subclass RTShape neither. The whole framework looks like it is based on builders and