You can change the duration of an animation by scaling its channel horizontally in the Channel Editor. This allows you to change the number of frames it takes for an animation to play through, without having to move each keyframe manually.

There are two methods to do this: using the XScale edit mode in the Animation Curve window, or by dragging the left or right handle of a track in the Track Editor.

Using XScale allows you to scale the channel using any keyframe as the origin of the scale. Dragging with a track's handle scales the track proportionally vis-a-vis the opposite handle.

When changing the length of channels, you may want to adjust the number of frames of the clip in the Total Frames field. For example, if you shorten the length of all the clip's channels, you can then shorten the clips' frames accordingly. Or, if you scale the channels longer than the duration of the clip, you can then add frames to account for this.

To use XScale on a channel or group of keyframes:

1. Display the Animation Curve window.
2. From the Edit Mode box, select XScale (or press spacebar+X).
3. Select a channel or several channels in the hierarchy.

   You may have to click Frame Chn to view the curve.

4. Click the keyframe that will act as the centre of the XScale. Drag left to decrease the value or drag right to increase the value of the other keyframes along the X-axis, relative to the selected keyframe.

   
   

   (a) Original animation curve  

   
   

   (a) XScale used to compress curves  

To scale a channel in the Track Editor:

1. Access the Track Editor.
2. From the Edit Mode box, select Move.
3. Select a track to access its handles.
4. Drag the left or right handle of a track.
   NoteIncreasing or decreasing the length of an animation may result in keyframes between frames. When this happens to the first or last keyframe, a decimal value is given to the keyframe value. See Snapping Keyframes between Frames.

   The track scales as you drag the handle vis-a-vis the opposite handle. All its keyframes are repositioned proportionally in time.

   
   

   (a) Original animation track  

   
   

   (a) Dragging handle used to compress a track from 40 to 20 frames  

   TipYou can move the handle of a folder to scale all channels in the folder. For example, moving the handle of the Scene folder (the top level folder) causes all the folders and channels in the hierarchy to be scaled by the same amount.