You can measure between the CoG- reference planes to part surfaces or origin planes:
https://help.autodesk.com/view/INVNTOR/2023/ENU/?guid=GUID-5A8F73C1-B19C-4DCA-85F3-B7AEF252632D
However, if you want some kind of point to lock onto, it seems to require some iLogic, such as this:
https://clintbrown.co.uk/2020/04/25/cog/
Note: The code is 4 years old and I haven't tried it.
Note 2: The code doesn't seem to update the position dynamically, which means you need to click the button to generate a new point at a correct position. Then any constraints etc must be redefined to the new point.