Layer bounding boxes and selection indicators help visualize the three-dimensional bounds for beveled, extruded, or curved layers, in addition to flat layers, the bounding boxes for selected 3D layers now appear as dashed and lighter outlines with scaling handles, with solid and slightly thicker lines at the corners. The back sides of the 3D bounding box are not drawn.
To help indicate the location of layers and if clicking will select them, the corner lines will appear above an unselected layer that would become selected if clicked at the mouse pointer's location. The same applies when marquee-selecting layers.
To show bounding box indicators around individual characters in per-character 3D text layers and nested layers in a collapsed precomposition, enable the Show Internal Wireframes option in Previews preferences. This option is enabled by default.
This video by Todd Kopriva and video2brain introduces you to the improved layer bounding boxes and layer handles introduced in After Effects CS6. We use these features to rotate an anchor point, reposition the anchor point, and snap the anchor point to different parts of the object.
When dragging a layer when Live Update mode is off (for example, when holding down the Alt key (Windows), or Option Key (Mac OS) when Live Update is enabled) or when viewing a composition in Wireframe preview mode (in the Fast Previews menu), an inverted "V" (instead of the old "X") will appear on the front face of the bounding box to indicate the "up" direction or top of the layer, and a small plus (+) will appear at the center of the bounding box to identify the center of the front side. Seeing the "V" orientation on 3D layers in Wireframe preview mode can be very helpful to identify their orientations.
You can also select the different sides of a 3D bounding box, and scale or rotate the layer based on the selected side. Scaling and rotation are relative to the layer's anchor point. You can also reposition the anchor point to the edges or centers of a visible side of the bounding box.
To scale a layer from a side of its bounding box: Using the Selection tool, select a side, and then drag one of the bounding box handles. Scaling occurs along the plane represented by that side.
Using the Rotate tool, select a side, then do either of the following:Drag a center handle along an edge to rotate around that edge's axis. Rotation around the x or y axis (when dragging the center handle) now behaves like that around the z axis, in that you need to drag around the anchor point instead of from side to side.
Drag a corner handle to rotate around the perpendicular axis.
Using the Pan Behind (Anchor Point) tool, start dragging the anchor point, then hold down the Ctrl (Windows) or Cmd (Mac) key as you approach an edge, center of an edge, center of a visible side, or center of the 3D bounding box. An edge will highlight (get thicker) when the anchor point is above it, the edges of a side will highlight when snapped to its center, and all edges will highlight when snapped to the center of the 3D bounding box. A small box will appear around the anchor point when above these center snap locations, and two small boxes will appear when above the center of the 3D bounding box.