This i my result from the Pivot Challenge, it was fun to try to create a regular door. I added hinges with the two hinge-parts split and merged into the the door and the door frame respectively.
I tried to align my 3D cursor along the hinges center z-axis but it didn’t get completely centered so i wonder how i would go about to figure out what xyz position and object is globally, and then how to find what position the center is. If anyone has any advices i say thank you in advance! ^ ^
Have you tried, selecting the appropriate edge loop or two opposing vertices, of the circle then clicking Shift-s (Cursor to selected)? That should put it in the mathematical center of the selected elements.
If you have made the hinges it should be easy. Select the hinge pin top face and move the cursor there. So long as you made everything straight and in line, it should work perfectly.