Absolute position of a Parented layer

[Wouter Dijkstra]

Point Control! That’s what I need. I was maybe doing something that wasn’t even possible. If I understand correctly: When there is a lot of layers parented to other layers, using the “absolute-expression” will always make the layer shift? Is that correct?

Thanks a lot for explaining so clearly and pushing me in the right direction!

[Walter Soyka]

[Wouter Dijkstra] “When there is a lot of layers parented to other layers, using the “absolute-expression” will always make the layer shift? Is that correct?”

Yes, and here’s what’s happening. When you make one layer a child of another, it assumes the coordinate system of its parent. When Ae renders the layer, it works through all the transformations for the layer: its transformations relative to its parent, its parent’s transformations relative to its grandparent, and so on.

When you ask for the absolute value in comp space, Ae will happily return it to you — but remember, Ae is following its parenting logic for transforms, and that requires coordinates to be relative to the parent’s layer space. Your expression causes the jump because you are smashing two separate frames of reference together.

Using the point control lets you see the value in a way that doesn’t actually affect the transform chain.

Does that make sense?

Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
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[Wouter Dijkstra]

Great to hear the actual explanation! ☺ Thanks for teaching me. I think I fully understand now. This whole situation kept me in the dark today, but I know how it works and what to do now. Thanks Walter!