Draft analysis lets you check parts and/or molds, to make sure they will seperate. Hopefully avoiding "locking" the part in the mold (or mould).
It will also detect undercuts and surfaces with no draft. Be carefull. It seems to work with open and shut dies. If you have a different slide the draft check will have to be ran more than once.
Here's a link to the NX11 documentation in Draft Analysis, with some examples:
"Use the Draft Analysis command to obtain visual feedback on the back draft condition of your part, and to define an optimum die press direction that minimizes back draft. The analysis can help you to avoid die-lock situations, make decisions on an appropriate parting line, obtain suggestions on cutter sizing for machining purposes, and others. "