CopyModel for Microsoft Project Server 2002/2003
Project Server Portfolio Modeller is a great tool that allow you do what-if modelling and compare your resource capacity against project demands. With Portfolio Modeller you can create different scenarios ("what will happen if we start projects A and B next month?", "what will happen if we start projects A, B and C this month", etc.) and later compare them.
The problem is that Project Server saves a model once you change any parameter and DON'T have to click Save to apply changes — all changes in model are saved automatically. So it may not be that easy to rollback to the original state of scenario you are analyzing.
CopyModel add-on allow you to save model at any state when you working on it and later compare different saved states. This makes comparing models easy and significantly enhances your analysis opportunities.