I would think that for most, if not all instances, CAD, FEA, CAM using a
helical sweep profile would be a detriment. I know that modeling
springs, bolts, etc... using helical features really bogs the regen
times down.
Stick with cosmetic.
Now, PTC needs to include some intelligence to the 'hole' type to help
the CAD/CAM system deal with interferences, and recognizing tapping
sequences as you should model the part in a 'stock safe' condition. OD
threads at the OD and holes at the tap drill dia.
Christopher F. Gosnell
FPD Company
124 Hidden Valley Road
McMurray, PA 15317