Animating object within object

[alter]

I have an object like this. I'd like to animate the rings rotating one within the other. The problem is as the outer ring rotates the angle and pivot location of the inner ring changes.

Any idea how In can make it rotate the way I want. Each ring rotates individually with all the rings inside it, but still remaining in its position inside the outer ring.

Thanks

[myara]

Simple, change the hierarchy to make all rings siblings.

If you don't want to change the hierarchy, you'll have to rig it.
Create controllers : create curves, constrain your objects to them, don't parent the controllers, and animate only the controllers.

[brad-price]

You need to preserve the ring's local rotation by grouping the rings while vertical and with zero rotation, then tilting the group rather than the ring itself:

1. Start with all the rings with no parenting or hierarchy.
2. Align all the rings so that their pins are vertical.
3. Group each ring individually - with it's outer pin included.
4. Rotate the groups (NOT the geo) to acheive the desired angle of the ring. The ring geo should now be sitting at an angle with a local rotation angle to match, but with zero rotation. You should be able to rotate Y to acheive spin on the geo.
5. Starting from the inner most ring, parent the group to the next ring's geo. Do this for all the rings.
6. Animate the rotate Y for each individual ring's geo. The rings should now spin about their hinges/pins while being spun by the rings outside of it.

Example hierarchy:

[ul][li]stand_GROUP

[ul][li]stand_geo

[ul][li]ring01_GROUP

[ul][li]ring01_geo

[ul][li]ring02_GROUP

[ul][li]ring02_geo

[ul][li]ring03_GROUP

[ul][li]ring03_geo

[ul][li]ring04_GROUP

• ring04_geo

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