Hi Randy, Good for you figuring the datum technique out on your own! Yes, it's irritating that you have to pay so many $'s for the Advanced Assembly extension. However, some of the techniques are still possible. For example, the software won't recognize and handle Skeleton Parts in an automatic way without the extension, but you can still use them; in "the old days", before automatic handling of Skeletons, it was already a technique. (You just create your own part with Datums, Surfaces, Curves, etc., add it as the first part in your assembly, then "hang" the parts and sub-assemblies on the skeleton like a hatrack. You can incorporate motion relationships into your skeleton, too (swing a Plane around an Axis, and your assembled parts will move with it). David