How is VR different from other tools, like RequisitePro or DOORS?
VR is positioned as a requirements development tool, though it includes also some requirements management functionality. This translates into increased visibility, efficient analysis features, specialized search features, etc. Tools like DOORS or ReqPro are first of all requirements management tools. Also, these and other tools are table-based tools. VR is based on a richer network metaphor, so you can organize requirements conceptually and visually. And VR includes means for building use case models, mocking up screens and investigating navigation, calculating size and effort of software systems, and so on.
