After Effects Pen Tool: Create Custom Shape Animations

The Pen tool is essential for creating custom shapes and path-based animations in After Effects.

Creating shapes with the Pen tool:
1. Select the Pen tool (G) from the toolbar
2. Make sure NO layer is selected (otherwise you'll create a mask, not a shape)
3. Click to create corner points, or click-and-drag to create bezier curves
4. Close the path by clicking back on the first point

Key distinction: Shape Layer vs Mask
- Pen tool with NO layer selected → creates a new Shape Layer
- Pen tool WITH a layer selected → creates a Mask on that layer

Animating the path:
1. Expand your shape layer → Contents → Shape → Path
2. Click the stopwatch on "Path" to set a keyframe
3. Move to a new time, then use the Pen tool or Direct Selection tool (V) to modify the points
4. After Effects interpolates between the two path states

Shape morphing (path A → path B):
Both shapes MUST have the same number of points. If shape A has 4 points and shape B has 6, the morph will look weird. Plan your shapes so point counts match.

Trim Paths animation:
1. Draw your shape
2. Add a Trim Paths modifier (Add → Trim Paths in the shape layer contents)
3. Animate the End or Start property from 0% to 100%
4. This creates a line-drawing reveal effect

Bezier handle tips:
- Hold Alt/Option and drag a handle to break the tangent (sharp corner on one side)
- Hold Cmd/Ctrl to switch to the Direct Selection tool temporarily
- Double-click a point to toggle between smooth and corner

Pro tip: Draw complex shapes in Illustrator first, then copy-paste into AE. The paths come in as shape layers with all your bezier points intact. This is faster than drawing complex paths directly in AE.