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How does After Effects calculate or determine a shape layer’s anchor point?
Hi,
I just want to understand how anchor point in shape layers works. When you create a solid, anchor point values are the distance from upper left corner. It’s straightforward. However, for shape layers, anchor points are always zero, even if I create them outside the composition. When I add
thisComp.layer("Shape Layer 1").width
thisComp.layer("Shape Layer 1").height
to the sourceText of a text layer, I learn Shape Layer 1 is a 1920*1080 layer just like my comp. It seems shape layer’s boundaries are the same as my comp. But then, shouldn’t anchor point values be 960*540?Thank you in advance.
Selçuk. -
4 Replies
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Well, apparently that’s how it works.
Shape layer’s boundaries don’t match comp boundaries but it does have the same size: it’s a 1920*1080 rectangle with top-left corner in the center of the comp.BTW, text layer is the same: it has the size of the comp and by default (when you double click on text icon) its top-left corner is in the center of the comp with zero anchor.
I could speculate that layers with variable Source Rectangle like texts and shapes are this way for convenience of dealing with point of origin: if you don’t manually change anchor point it will mark the origin.
Layers with fixed Source Rectangle like solids, nested comps, footages don’t need that cause origin is always marked as Source Rectanlge’s top-left corner.
But those are just my guesses and lyrics.In the end of the day, all layers have it’s origin in their top-left corner and anchor point coordinates are giver with respect to it. The thing that differs is Anchor Point and Position default values.
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Thank you very much for your detailed answer even though it still doesn’t make sense to me. I guess I’ll accept as it is and move on.
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>origin is always marked as Source Rectanlge’s top-left corner
This is not “always”. In case of masks applied, for instance. And “fixed/variable source rectangles” are loose terms invented by me. -
I don’t know if this will be of any help, but I’ve just recently been working on expressions to manipulate the anchor point position. I have a shape layer box that adjusts its size to some text. I want to transition the box on by scaling from 0 to 100% so it looks like the box is wiping on from right to left. The expression pins the anchor point to the top left of the box and the position is an absolute.
var sourceRect = sourceRectAtTime(time);
[sourceRect.left + sourceRect.width , sourceRect.top]I built this for a template to import into Premiere so the editor can edit lower-thirds.
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