I have an Xcode project written in Objective C and I am trying to create a UML diagram. However, the project is too big for me to create by hand so and I can't find the class modeling function in Xcode4. Is there a free UML program that I can import my xcode project and automatically generates the UML diagram?
Take a look at OmniGraffle should be able to draw UML diagram for your code.
Another option could be Visual Paradigm .