I’m wondering why you prefer collaboration diagrams over sequence diagrams?

They have very low information content and I find them too cumbersome for all but the simplest interaction.

I really like sequence diagrams for documenting some key interactions in a system, I’ve even created my own UML sequence diagram editor Trace Modeler. It is actually faster than drawing on any whiteboard.

One remark about your text where you speak of several models. There really is only one model, in your case it’s your program. The diagrams are simply views onto this model.

If you give Trace Modeler a try, let me know what you think of it, I’m always happy to get feedback! Here’s a 30 sec demo of Trace Modeler in action to get you interested ;o)

Best regards,
Yanic