How do I view my class model using xcode4 or another tool?

Is there a way to view the entire class model for my project gra开发者_StackOverflow中文版phically? I have several classes and I'd like to see things like someClass 'is a' window and 'has a' frame. I know I could use something like OMNIGRAFFLE and make one myself but is there something built into xcode4 or some other tool that does this?

I use Visual Paragdim UML for that. It creates both code from UML and an UML graph from code. Check out this tutorial to see how.

Previous versions of Xcode had a class modeler but this was removed in Xcode 4. Presumably it wasn't a popular enough feature to make the cut into v4. No word on whether they plan to add it back into some future 4.x version.

I needed this to help me analyse an existing project that I'll have to maintain and I found Autograf. Even though it seems not to be actively maintained it still works.