Transforming Child objects with multiple parents

Question

Context :

I have a collection of objects that make up a whole door. These consist of

Door leaf Door Frame Expanding Frame Door Handle Various bits and bobs that make up the locking mechanism, hinges etc

I've parented all of these objects to an empty - this allows me to rotate the whole collection whilst keeping everything positioned correctly.

My question is, if i wanted to show the door slightly open, I would need to keep the frame in place, but rotate on the following around the hinges z axis

Can i create an additional empty that only controls the parts that should move. My intention is to angle the WHOLE door by 30 degrees, and open the door about half way.

How would i control this using objects parented to empties? I know i could do it manually object by object but my ( lack ) of experience tells me there must be a way to parent individual collections to individual empties.

FYI I have tried creating a collection just for the door opening objects, however the resulting empty doesn't appear to control any movement, as if blender is only considering the original 'whole door' parent relationship

Many thanks in advance

Answer 1

AFAIK you cannot parent a collection to an object.

But it is pretty easy to parent multiple objects to one object/empty: just select all objects you want to parent to the same empty, then shift-select the empty, press ctrl-p -> object (keep transform).

I would use this easy setup here:

• all blue objects (which are part of the moving door) are parent to the "open door controller"
• all orange parts (which are part of the frame) are parented to master controller
• the open door controller itself has the master controller as parent too

result:

Hint: for easier use of the open door controller you can lock location + 2x rotation like this: