If you have already started to take your first steps in After Effects, you will have noticed that the program does not have a typical trimming tool, as other Adobe products designed for video editing, such as Premiere, do. That is why actions as simple as selecting only a part of your video and getting rid of the rest, may seem complex at first when they’re not.
So don't worry when you want to make your first creation and you don't know how to trim your clips in After Effects or how to place them along your Timeline, just read on and follow the three steps below.
Rename your Layers to make it easier to identify and manage them in the Timeline by right-clicking on the imported files you brought from the Project Panel. Then select the Rename option and type the new name.
Now that you have your files ready to manipulate, you can see that each one has its layer on the Timeline, so the first one overlaps the second one, and so on. Well, it is possible to turn layers on and off in After Effects.
Once you set the visibility of the layer you want to work on, place it above your other layers on the Timeline so you can add adjustments to it. Highlight it by clicking on it.
Let's say your video is longer than 30 seconds and you only want to work with the first four, for now. Well, to cut it at 00:04 and get rid of the rest of the footage:
1. Move the Time Indicator to the desired second (in this case, 00:04).
2. Press Cmd + Shift + D on the keyboard to cut it.
3. Get rid of the rest of the footage by selecting its layer and hitting Backspace on your keyboard.
Since Adobe After Effects does not have a “cut” tool icon, this shortcut would replace that function. Keep in mind that every time you use it, a new layer will be added to the Timeline so you can decide whether to keep the rest of the video or just the part you cut.
Tip: If you feel that you cut too much of your video and need to recover its parts or even restore its original length, go to its layer and place your mouse at the end of the clip fragment. Then, drag it to the right to lengthen it to the desired second.