Trying to noodle through a problem I'm having and could use a hand. I did search the forums but didn't find a clear answer.
Let's say I import an image of an regular sized postal envelope into After Effects and keyframe this envelope moving all around the comp. It rotates on the Y axis, moves in X, Y, and Z space, and its opacity changes.
I now want to add a stamp to the corner of this envelope (after I've done all my keyframing with just the envelope.) I essentially want the stamp stuck to the envelope and want to move around in x, y, and z space and rotate along with the envelope.
Obviously, establishing the stamp as the child and the envelope as the parent should work BUT
I know that After Effects doesn't recognize opacity, rotation, or 3d space in terms of parent child relations.
What's the best way to acheive this?
1) Obviously, if I went back in time, I could find an image of an envelope with a stamp already attached and replace the image I'm already using. Sounds simple enough but no fun.
2) Or delete all my keyframes and pre-compose the stamp on top of the envelope and import the new pre-comp, movong it around as a single element.
3) Or, I could create a null object and parent the null to the envelope and parent the null to stamp too ... Now when I move the null around in Z space... Will that work?
4) Or do I need to employ expressions somehow...
Bottom line: What's the best way to employ parent child relationships when working with 3d space, rotation, and opacity... All parameters NOT recognized by After Effects in traditional child parent relationships.
Precompose the envelope layer, leaving all attributes in the Main Comp.
Open the precomp, add your stamp layer and position it where you want.
It's now connected in the Main Comp.
By the way, 3d transforms, including rotation, are respected in a parent/child relationship as long as both layers have their 3d switches enabled.
And if you wanted, you could just pickwhip an expression linking the layers' opacities. But that's less flexible and more work than necessary for what you need.