When you make a layer a 3D layer, the layer itself remains flat, but it gains additional properties: Position (z), Anchor Point (z), Scale (z), Orientation, X Rotation, Y Rotation, Z Rotation, and Material Options properties. Material Options properties specify how the layer interacts with light and shadows. Only 3D layers interact with shadows, lights, and cameras.
Individual characters within text layers can optionally be 3D sublayers, each with their own 3D properties. A text layer with Enable Per-character 3D selected behaves just like a precomposition that consists of a 3D layer for each character. All camera and light layers have 3D properties.
By default, layers are at a depth (z-axis position) of 0. In After Effects, the origin of the coordinate system is at the upper-left corner; x (width) increases from left to right, y (height) increases from top to bottom, and z (depth) increases from near to far. Some video and 3D applications use a coordinate system that is rotated 180 degrees around the x axis ; in these systems, y increases from bottom to top, and z increases from far to near.
You can transform a 3D layer relative to the coordinate space of the composition, the coordinate space of the layer, or a custom space by selecting an axis mode.
You can add effects and masks to 3D layers, composite 3D layers with 2D layers, and create and animate camera and light layers to view or illuminate 3D layers from any angle. When rendering for final output, 3D layers are rendered from the perspective of the active camera. (See Create a camera layer and change camera settings.)
All effects are 2D, including effects that simulate 3D distortions. For example, viewing a layer with the Bulge effect from the side does not show a protrusion.
As with all masks, mask coordinates on a 3D layer are in the 2D coordinate space of the layer.
When you convert a layer to 3D, a depth (z) value is added to its Position, Anchor Point, and Scale properties, and the layer gains Orientation, Y Rotation, X Rotation, and Material Options properties. The single Rotation property is renamed Z Rotation.
When you convert a 3D layer back to 2D, the Y Rotation, X Rotation, Orientation, and Material Options properties are removed, including all values, keyframes, and expressions. (These values cannot be restored by converting the layer back to a 3D layer.) The Anchor Point, Position, and Scale properties remain, along with their keyframes and expressions, but their z values are hidden and ignored.
3D axes are color-coded arrows: red for x, green for y, and blue for z.
If the axis that you want to manipulate is difficult to see, try a different setting in the Select View Layout menu at the bottom of the Composition panel.
Chris and Trish Meyer provide a video tutorial on the ProVideo Coalition website that demonstrates the use of the 3D axis layer controls.
Press P to show Position.
You can turn a 3D layer by changing its Orientation or Rotation values. In both cases, the layer turns around its anchor point. The Orientation and Rotation properties differ in how the layer moves when you animate them.
When you animate the Orientation property of a 3D layer, the layer turns as directly as possible to reach the specified orientation. When you animate any of the X, Y, or Z Rotation properties, the layer rotates along each individual axis according to the individual property values. In other words, Orientation values specify an angular destination, whereas Rotation values specify an angular route. Animate Rotation properties to make a layer turn multiple times.
Animating the Orientation property is often better for natural, smooth motion, whereas animating the Rotation properties provides more precise control.
Shift-drag to constrain your manipulations to 45-degree increments.
Press R to show Rotation and Orientation properties.
Donat Van Bellinghen provides some expressions on the AE Enhancers forum for placing and orienting a 3D layer in the plane defined by three points.
Axis modes specify on which set of axes a 3D layer is transformed. Choose a mode in the Tools panel.
Local Axis mode
Aligns the axes to the surface of a 3D layer.
World Axis mode
Aligns the axes to the absolute coordinates of the composition. Regardless of the rotations you perform on a layer, the axes always represent 3D space relative to the 3D world.
View Axis mode
Aligns the axes to the view you have selected. For example, suppose that a layer has been rotated and the view changed to a custom view; any subsequent transformation made to that layer while in View Axis mode happens along the axes corresponding to the direction from which you are looking at the layer.
Differences between the axis modes are only relevant when you have a 3D camera in a composition.
The Tools panel remembers the last-used 3D axis mode when you quit and restart After Effects.
The Camera tools always adjust along the local axes of the view, so the action of the Camera tools is not affected by the axis modes.
Angie Taylor explains 3D axis modes in this tutorial.
The positions of certain kinds of layers in the layer stacking order in the Timeline panel prevent groups of 3D layers from being processed together to determine intersections and shadows.
A shadow cast by a 3D layer does not affect a 2D layer or any layer that is on the other side of the 2D layer in the layer stacking order. Similarly, a 3D layer does not intersect with a 2D layer or any layer that is on the other side of the 2D layer in the layer stacking order. No such restriction exists for lights.
Just like 2D layers, other types of layers also prevent 3D layers on either side from intersecting or casting shadows on one another:
An adjustment layer
A 3D layer with a layer style applied
A 3D precomposition layer to which an effect, closed mask (with mask mode other than None), or track matte has been applied
A 3D precomposition layer without collapsed transformations
A precomposition with collapsed transformations (Collapse Transformations switch selected) does not interfere with the interaction of 3D layers on either side—as long as all of the layers in the precomposition are themselves 3D layers. Collapsing transformations exposes the 3D properties of the layers that compose the precomposition. Essentially, collapsing transformations in this case allows each 3D layer to be composited into the main composition individually, rather than creating a single 2D composite for the precomposition layer and compositing that into the main composition. The tradeoff is that this setting removes your ability to specify certain layer settings for the precomposition as a whole—such as blending mode, quality, and motion blur.
Shadows cast by continuously rasterized 3D layers (including text layers) are not affected by effects applied to that layer. If you want the shadow to show the results of the effect, then precompose the layer with the effect.
To ensure that the shadow remains where expected on a 3D layer with a track matte, precompose the 3D layer and the track matte layer together (but don’t collapse transformations), and then apply the shadow to the precomposition.
Effects on continuously rasterized vector layers with 3D properties are rendered in 2D and then projected onto the 3D layer. This projection does not occur for compositions with collapsed transformations.