Use the grid already in the comp

Lay markers before using the four editing buttons. They use comp BPM markers first. If the comp has none, they combine BPM markers from all layers, including unselected layers. Other marker comments are ignored.

This means an older comp grid takes priority over a newer layer grid. Clear or replace the old markers if you want to change which rhythm drives the edit.

Select the layers or keys you want to change. Locked layers are skipped and counted in the result. A locked-only selection is refused. Every action has one After Effects undo step.

Align a layer edge

Select layers and click Snap. Each whole layer moves so its in point lands on the nearest grid marker. Its length stays the same. Shift-click for Snap out, which moves the whole layer to align its out point instead.

For example, with markers every 0.5 seconds, an in point at 1.2 seconds moves to 1 second. At an exact tie between two markers, BPM chooses the earlier one.

Alt-click Snap for Trim out. This changes only the out point. The layer stays in place.

Trim out chooses the nearest valid marker to the current out point. It can shorten or extend the layer.

A valid trim marker must be more than half a frame after the in point. For normally playing footage or a precomp, BPM also avoids extending past the source end. That source limit does not apply to time-remapped layers, stills, or reverse-stretched layers.

Arrange layers along the rhythm

  1. Select the layers to arrange.
  2. Set Beats per layer in Settings. Leave it at 1 for one grid interval each.
  3. Click Sequence.

Sequence uses Timeline stack order, top layer first. It starts at the marker nearest the earliest in point among the selected unlocked layers. It moves each layer to its assigned marker and adjusts its out point to the next slot.

On a 120 BPM 1/1 grid starting at zero, three two-second solids with in points at zero become spans of 0 to 0.5, 0.5 to 1, and 1 to 1.5 seconds.

Beats per layer counts grid-marker intervals. At 1/2, a setting of 2 gives each layer one full beat. At Bar, 1 gives each layer one bar.

Shift-click for Reverse, which starts with the bottom selected layer. Alt-click for Place, which keeps each layer’s length while changing its start. You can hold Shift and Alt together to reverse the order and keep lengths.

Sequence can continue beyond the last marker by repeating the last marker gap. Sequencing several layers needs at least two markers. Ordinary moving footage is capped at its source end, so a short clip may leave a gap. BPM leaves a proposed out point unchanged if it would make the layer shorter than one frame.

Cut a layer at every marker

Select one or more layers and click Split. BPM keeps the first segment on the original layer and creates duplicates for the later segments. It selects the resulting pieces.

Only markers strictly inside the layer are cuts. Markers within half a frame of either edge are excluded. A two-second layer over markers at 0, 0.5, 1, and 1.5 seconds becomes four half-second pieces.

Align selected keyframes

Select keyframes in the Timeline and click Keys. Selecting a layer or property alone is not enough. Layer-marker keys are excluded.

Each selected key moves to its nearest grid marker with its value. BPM also carries interpolation, easing, spatial tangents, and supported key labels with it. Keys remain selected after moving.

BPM leaves a key where it is if its destination already has an unselected key. When selected keys compete for one destination, the closer key wins; equal-distance ties favor the earlier selected-key entry. These rules avoid deliberately replacing an existing key.

Already on the beat can also mean nothing could move because of a collision, a source limit, or a lack of valid cut or trim times. Inspect the selection and markers before retrying. No grid means no recognized BPM markers were found.