Details
When trying to create Arbitrary PMI region using a face and curves on that faces, "Arbitrary PMI region must have at least one valid area" error occurs and PMI region cannot be created.
However PMI region can be created when selecting only the curves on the face.
Solution
If a combination of curves and faces are selected, the curves must be coplanar.
This is a design limitation and the same is mentioned in NX documentation.
Hardware/Software Configuration
Platform: INTL64
OS: windows
OS Version: 1064
Product: NX
Application: PMI
Version: V1934
Function: REGIONS
Ref: 002-8566893