# Dynamically change pivots of an object

Is it possible to rotate one object (A) around another object's origin (B) without transforming A's origin to B's? I need this because I want to rotate A around several objects successively. I know this can be done with the "Follow Path" constraint, but it is a complicated method. Also note that the "Pivot" constraint can be used only once and cannot be changed dynamically (or at least I don't know how it does).

Thanks.

• If I understand your project correctly a simple method would be to place an empty at B's origin and parent A to that and rotate the empty. Move/transform the Empty from object to object when required. Apr 21, 2017 at 16:12
• You can generally parent an object to an empty placed at the desired center of rotation, though I don't know how to do it for several different points Apr 21, 2017 at 16:50
• Do you need the rotation for an animation? Apr 21, 2017 at 17:50
• @Edgel3D: And then I'll "clear parent + keep transformations" the empty and keyframe the location of A? It's a bit less parametric than I'd like, but ok. Thanks
– Log
Apr 21, 2017 at 19:07

I found the general solution to "dynamically change any constraint" which subsumes "dynamically change pivot". It's simple: Change the "Influence".

Flowchart:

1. Create (stack) as many pivot constraints as required and target them to the respective objects (or empties).

2. Set "Influence" of all the pivots to "0" before creating any key-frames.

3. For the first rotation about (suppose) the x-axis, key-frame the x-rotation and set Influence to 1.

4. Scrub frames till a, rotate as required and key-frame x-rot.

5. Now to blend this with the second rotation, scrub a few (k) frames back till a-k, key-frame the first Pivot's Influence (now at 1) and also key-frame the second Pivot's Influence (at 0).

6. Scrub forward to a+k frame and switch the values of the first and second Pivots' Influence; key-frame both.

7. Scrub frames and setup the second rotation as before (Step 4.), and so on.

I endorse this method over other simpler Transformation methods since this is parametric and has few dependencies.