需要 UML 工具？

Visual Paradigm Online Free Edition is a free, easy-to-use web based UML tool. It gives you the tools to draw UML diagrams and other diagrams like ERD, Organization Chart and Floor Plan. With multiple diagram template and an intuitive diagram editor, this UML tool lets you direct all of your energy into visualizing your ideas and not into fumbling through complicated menu and pop-ups. The software is free for non-commercial use. You can create unlimited number of diagrams and shapes, and export diagrams into images.