Fixed Datum Planes can be resized (Edit-Feature-Resize Fixed Datums), but it didn't seem to make any difference in their size until I did it in NX V1. I tried V16.0.4 and V18.0.5.
Feature related planes should update when the feature changes size. Ben Loosli
CAD/CAM System Analyst
Ingersoll-Rand
Note that the size of the datum depends on the amount of zoom used when using the method above. Zoom in for smaller datums and zoom out for larger datums.
I had the same problem,
we are using a simple shortcut to achieve it.
1.Put a very big block(using block option)to the size of the model you have.
2.Now use the resize fixed datum planes,Now your fixed datum planes sizes will change.
(i have tried in UG 18 it is working fine)
3.Delete the block you have created.
I believe there is no other method to achieve it.