Arent prototyping tools doing the same as VR?
Traditionally, prototyping tools do not support modeling. They are for later stages of working on a system, because you build a prototype after at least some business analysis has already been done. VR is about doing this business analysis; but it also enables screen mock up to make requirements better understandable. VR does not target to be a prototyping tool; it supports the work on the concept of the system when it is not that clear yet what has to be built and when there is a lot of textual material to be organized, linked, analyzed, and so on.
