How to make an object rotate in Adobe After Effects?

To make an object rotate in Adobe After Effects, you'll primarily use the Rotation property of the layer. Here's how you can achieve rotation, covering both simple and more advanced techniques:

Basic Rotation

1. Select the Layer: Choose the layer you want to rotate in your composition.
2. Open Transform Properties: Press the 'R' key to reveal the Rotation property.
3. Adjust Rotation: Click and drag the rotation value to rotate your object, or type in a specific degree value. You can use full rotations (360 degrees) and beyond. The Rotation property has two number values; the first one is the number of full rotations, and the second is the degrees the object is rotated.

Keyframing Rotation for Animation

To create a rotation animation:

1. Set the First Keyframe:
   • At your desired start time on the timeline, click the stopwatch icon next to the Rotation property to create a keyframe.
2. Move in Time and Adjust Rotation:
   • Move the playhead to a later point on the timeline.
   • Adjust the Rotation property to the desired end position of the rotation. After Effects will create another keyframe automatically.
3. Playback: Now, when you play your animation, the object will rotate between these two keyframed values.

Constant Rotation

To make an object rotate continuously:

• Use the Time Expression: As shown in the reference video, you can create a continuous rotation using the time expression. In the rotation property, hold the Alt key and click on the stopwatch to add an expression. Write the expression time*speed and change the value of speed to control the rotation. Positive values will rotate the object clockwise, while negative values will rotate counterclockwise.
• Adjust the Speed: Change the speed to control the rotation rate.

Example using Time Expression (from referenced tutorial)

• Select your layer and press 'R' to open the rotation property.
• Hold Alt/Option and click on the stopwatch next to the rotation to add an expression.
• Type in the following: time*100 to rotate at a speed of 100 degrees/sec. You can use other values as desired. Use negative values for a reverse direction.

Rotation Using Anchor Points

• Adjust the Anchor Point: The object rotates around its anchor point. By default, it's at the center, but you can change its position for different rotation effects.
• Tool: Use the Pan Behind (Anchor Point) Tool (shortcut: Y) to reposition the anchor point.

Additional Tips

• Easing: Use easing for smoother transitions between rotations using keyframe interpolation. Right-click on keyframes, go to Keyframe Assistant, and select the desired ease preset, like Easy Ease.
• Parenting: You can parent a layer to another layer or null object for more complex rotation movements.
• Expressions: Use expressions to programmatically control the rotation (mentioned before).

By combining these basic and advanced techniques, you can create complex and engaging animations using object rotation in After Effects.