How to Animate Strokes with Trim Paths in After Effects

A workflow taught by Adobe Certified Instructors at Adobe Video World.

Trim Paths is the tool behind self-drawing lines, animated icons, and write-on effects — strokes that appear to draw themselves onto the screen. It’s one of the most useful features for motion graphics, turning any shape’s outline into an animation. This guide explains how Trim Paths works and how to use it for stroke animations.

What Trim Paths Does

Trim Paths animates how much of a shape layer’s stroke is visible, revealing it progressively along its path. By animating from nothing to the full stroke, you make a line or outline appear to draw itself onto the screen.

This drives a huge range of effects — animated signatures, self-drawing icons, underlines that sweep in, and outline reveals. Any path you can draw, Trim Paths can animate drawing on, which makes it indispensable for clean motion design.

Start with a Shape Layer Stroke

Trim Paths works on shape layers, so begin with a path that has a stroke. Draw a line, an icon, or any shape with the pen or shape tools, and give it a stroke with no fill, since it’s the stroke that will animate on.

The path can be a simple straight line or an intricate outline — Trim Paths handles both. Building clean shape layers, as our shape layers guide covers, gives Trim Paths good paths to animate along.

Add Trim Paths to the Shape

With your shape selected, click Add in the shape layer’s contents and choose Trim Paths. This adds Trim Paths properties — Start, End, and Offset — that control how much of the stroke is drawn.

Start and End define where the visible portion of the stroke begins and ends, as percentages of the path. Animating these is how you make the stroke appear to draw on or wipe away.

Animate the Stroke Drawing On

The classic write-on is simple: keyframe the End property from 0% to 100%. At 0% none of the stroke is visible; as End animates to 100%, the stroke draws progressively along the path until the whole shape appears.

This single keyframed property creates the self-drawing effect. Reversing it — animating End from 100% to 0% — makes the stroke erase itself, and animating Start instead wipes from the other direction.

Use Offset for Moving Dashes

The Offset property shifts the trimmed section along the path without changing its length. Combined with a dashed stroke, animating Offset creates marching, flowing dashes — perfect for animated borders, routes, and progress indicators.

This is how you make a dashed line appear to travel, like a moving path on a map or a loading animation. Offset adds motion to the stroke itself, expanding what Trim Paths can do beyond a simple draw-on.

Ease the Animation

A linear Trim Paths animation can feel mechanical, so easing improves it. Apply Easy Ease to the End keyframes and shape the velocity so the stroke accelerates and decelerates as it draws, giving the motion a natural, hand-drawn quality.

Easing is especially important for signatures and organic shapes, where even speed looks robotic. Refining the timing in the graph editor, as our keyframe guide explains, makes the draw-on feel deliberate and smooth.

Animate Icons and Signatures

Trim Paths excels at line-art animation. Trace an icon or a handwritten signature as a stroked path, then animate End from 0 to 100%, and it draws itself on as if by an invisible pen — a polished, professional effect.

For multi-part icons, put each stroke on its own path and stagger their Trim Paths animations so they draw in sequence. This builds complex self-drawing illustrations that are a hallmark of explainer videos and modern motion graphics.

Combine Strokes with Fills

Many animations draw an outline on and then fill it. Animate the stroke with Trim Paths first, then fade or scale in a fill once the outline completes, creating a satisfying build from line to solid shape.

This outline-then-fill technique gives logos and icons a designed, animated reveal. Layering Trim Paths with other property animations, within the broader workflow of our motion graphics guide, turns a flat shape into a dynamic sequence.

Trim Paths Best Practices

• Start with a shape layer that has a stroke and no fill.
• Animate the End property from 0% to 100% for a draw-on.
• Use Offset with dashes for marching, flowing lines.
• Ease the animation for natural, hand-drawn movement.

Common Trim Paths Mistakes

• Applying Trim Paths to a fill instead of a stroke.
• Linear keyframes that make the draw-on feel robotic.
• Animating one path when each stroke needs its own.
• Forgetting Offset for moving dashed-line effects.

A Real Write-On Logo Example

Say you have a hand-lettered logo you want to draw itself on. You trace the lettering as stroked shape paths, add Trim Paths to each stroke, and keyframe every End from 0 to 100 percent, staggering them so the letters draw in sequence like a pen writing the word. Easing each one gives the motion a natural, handwritten rhythm.

Once the outline finishes drawing, you fade in a solid fill version of the logo beneath, so the line art resolves into the final mark. This outline-then-fill build, a Trim Paths staple, gives a logo a satisfying, crafted reveal that feels far more designed than a simple fade or scale.

Animate Maps and Routes with Trim Paths

Trim Paths is the standard way to animate a route drawing across a map. You draw the path of a journey as a stroked line, add Trim Paths, and animate End from 0 to 100 percent so the route extends from start to destination, often with a marker parented to the end of the line to lead the way.

Adding a dashed stroke and animating Offset can make the route look like a moving trail, reinforcing the sense of travel. This technique powers the travel-vlog and explainer map animations seen everywhere, and it combines naturally with the motion graphics skills used to build the rest of the scene.

Key Takeaways

• Trim Paths reveals a stroke progressively along its path.
• Animate End from 0% to 100% for a self-drawing line.
• Use Offset with dashes for marching-line effects.
• Ease the animation and stagger strokes for complex icons.

Frequently Asked Questions

How do I use Trim Paths in After Effects?

Select a shape layer with a stroke, click Add in its contents, and choose Trim Paths. Then keyframe the End property from 0% to 100% to make the stroke draw itself onto the screen.

Why isn’t my Trim Paths animation showing?

Trim Paths animates the stroke, not the fill, so your shape needs a visible stroke. Make sure the path has a stroke applied, and that you’re animating the Start or End property, not a fill.

How do I make a dashed line move with Trim Paths?

Add a dashed stroke to your shape, then animate the Offset property in Trim Paths. Offset shifts the stroke along the path, making the dashes appear to march or flow continuously.

Sources: Adobe’s guide to animating shapes and strokes.