Using Empties

Can I use an empty to create a second pivot point on an object? Is that the normal way to do it?

You can parent (Ctrl+P) or use a Child Of constraint on an object to parent it to an empty and then rotate the empty

Okay, I think I understand now.

My problem seems to be that I can’t figure out how to properly limit the rotation of a pivot point (an empty) that I placed midway along a movable arm whose origin is at one end where it attaches to a main body. The arm should be able to rotate freely in any direction, but the empty should only rotate on whatever axis the arm is pointing. Normally, a parent/child relationship would handle it correctly, but with this second pivot point I’m a little confused about how to set this up. I spent two full days trying to work it out and now I’m totally confused.

How do I set it up? Here’s what I did:

  • Set up the arm (set origin to one end and then parent it to the main body)
  • Join an empty at the midway point of the arm.
  • Parent a secondary object to the empty that will rotate on the empty (the secondary arm’s origin is set to where the empty is).

What am I doing wrong? Do I have to limit the rotation of the empty even if it’s part of the arm object?