Hello! Starting in After Effects Beta v23.3 build 9, you can now snap layers in 3D space while dragging the constrained X, Y, and Z position handles of the 3D gizmo.
This new behavior is in addition to non-constrained snapping, which has worked with 3D layers since snapping was introduced in After Effects many years ago. Non-constrained snapping is when you reposition a layer by clicking on an arbitrary point on that layer and snap it to another layer.
There's actually quite a lot of subtlety to snapping! If you're not familiar with how snapping works in After Effects, here's a great overview video. This was made when snapping was introduced in a much, much older version of After Effects, but the basic principles still apply.
What's new and different today is that snapping now works when you click and drag on the X, Y, and Z handles of the 3D gizmo. This includes the XY, XZ, and YZ combo handles of the 3D position gizmo.
Previously, dragging the gizmo handles simply wouldn't snap.
The tricky part with constrained snapping, compared to non-constrained snapping, was translating the onscreen 2D movement of your mouse to the 3D space of the comp. With non-constrained snapping, the snap points are calculated only in the X,Y coordinates of your screen. With constrained snapping in 3D space it's harder because the screen coordinates of your mouse movement need to be translated to the X,Y,Z 3D coordinates of your comp. This translation is affected by the camera and view settings of your Composition viewer and needed some finessing to make the snapping feel "natural". (For example, when a layer is snapped, how much does it move in 3D space?)
One difference to be aware of with constrained 3D layer snapping is that the snap point on the layer being dragged is always that layer's anchor point. With non-constrained snapping, the snap point is the handle nearest to where you clicked on the layer.
And, yes! Snapping, both constrained and non-constrained, does work with 3D model layers in After Effects Beta.
This is one of many improvements we've been working on for 3D workflows in After Effects. We want to hear your feedback about it. Whether you experience any problems with it, would like to see improvements, or just love it as-is. Thank you!
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