What is your favorite Free or Open-Source UML Plug-in?

Every year I try some of them and remove them after few hours. As I remember, they were resource-hungry or just bad in reverse engineering

Some weeks ago i tried ObjectAid UML Explorer Class Diagram and liked it. It could quickly and easily create simple class Diagrams - just by Drag & Drop. And I had no problems with static constructors or inner classes and other stuff in the code which causes problems to other Plug-ins.

Unfortunately, Object Aid Sequence Diagrams are not free but cost not much for private usage. Maybe I’ll try it soon.

But first I would ask you what is your favorite Eclipse IDE Plug-in for fast and easy (e.g. partly) reverse engineered UML diagrams which can be used to show some architectural details to your colleagues?

Thank you for your comments!