Put the name of the dra/psm into Capture CIS PCB Footpriint property, i.e. if your footprint is called soic8.dra/psm then put soic8 in the PCB Footprint property of the part in capture CIS.
Inside PCB Editor there is a Display - Measure command, make sure the correct items are enabled in the Find Filter (fold out menu on the right hand side) and then select the items you wish to measure. You'll see a popup box with the dimension information,x,y airgap etc.
You can renew parts. If you make a change to the dra/psm file go to the board that uses it and use Place - Update Symbols, select the relevant items and click on Refresh.