How to animate a parent swap ?

Hi there

anybody has an idea how to animate a parent swap for one object where in the beginning rotations from one empty/parent left is being used and in the end the rotation from a second empty/parent right is being used.

Think about an open door closing and then in the end opening again but to the other side.

I know there is a child of constraint but this one lines up the door mesh center with the empty center - so this does not work.

If I understand you correctly you could use Pivot constraints instead of Child of constraints.

door.blend (382 KB)

AFAIK the parent/child relationship can’t be animated, that’s why the Child Of constraint was invented. If that doesn’t work for you, you’ll have to find a different approach than parenting.

Could you post the .blend or a simplified version to look at? It’s difficult to suggest alternatives with such a limited description of the setup.

“Copy Rotation” and “Copy Location” constraints would probably do the trick for a door going both ways.

Edit: Actually, probably not, since the pivot point is changing; you would need a Parent/Child relationship since the origin of the rotation is different for the two sides.

AlanK, this is actually what really works when considering the pivot point for rotation along switching axis.

Just a positional option would be great as well in a relative way like with a parenting.

I wish the parent/child constraint would be able to have this relative function and would not snap the child right to the parent center by default.

After working with this pivot modifier we really need a better parent modifier.

We should make this a feature suggestion.

If I understand correctly, what I have done in the past is embedded parenting. See attached blend. The empty on the right is parented to the empty at origin. First the empty at right rotates, then the empty at left. Scrub through the timeline to see the result.

DoorPivot.blend (710 KB)

Hi Daren,

ah I see what you mean with embedded parenting. That works pretty well as long as you do not use curves along which the empties flow along. Than you will get an issue with the child empty.

Copy Location, Pivot constraints seem all to follow a very specific singular function.

Whats actually odd is that I just now again tried the child of constraint with the set inverse option and it behaved like what I am looking for. Previous attempts did not work - strangely. I am not sure if it is a bug.
Maybe this should also be called keep relative location/distance instead like the normal parenting command.

Here is a blend file showing you what I was looking for - but great this trip made me test the pivot tools as well :wink:

Frame 50 to 100 would be the desired motion effect inside the blend for me: