CSS Academy · Lesson

Animating clip-path Shapes

Create dramatic reveal animations by transitioning between clip-path polygon values.

Animating clip-path Shapes is a free CSS Academy lesson on CoddyKit — lesson 3 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the CSS Academy learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.

Animatable clip-path

CSS can transition and animate between two clip-path values as long as both are the same shape function with the same number of arguments. Interpolation is point by point.

Slide Reveal Animation

A classic clip-path reveal — content slides in from left:

.content {
  clip-path: polygon(0 0, 0 0, 0 100%, 0 100%);
  transition: clip-path 700ms cubic-bezier(0.4, 0, 0.2, 1);
}

.content.visible {
  clip-path: polygon(0 0, 100% 0, 100% 100%, 0 100%);
}

Circular Reveal

Expand a circle from center to reveal content:

.overlay {
  clip-path: circle(0% at 50% 50%);
  transition: clip-path 500ms ease;
}

.overlay.open {
  clip-path: circle(150% at 50% 50%);
}

Shape Morphing

Animate between polygon shapes for a morphing effect. Both polygons must have the same number of vertices:

@keyframes morph {
  0%   { clip-path: polygon(50% 0%, 100% 100%, 0% 100%); } /* triangle */
  50%  { clip-path: polygon(0% 0%, 100% 0%, 100% 100%, 0% 100%); } /* extra point needed */
  100% { clip-path: polygon(50% 0%, 100% 100%, 0% 100%); }
}
/* Note: different vertex counts cannot interpolate — match them */

Matching Vertex Count

To animate between different polygon shapes (e.g., triangle to square), add extra coincident points to the simpler shape:

/* Triangle with 4 points (two at same position) */
polygon(50% 0%, 100% 100%, 0% 100%, 0% 100%)

/* Square with 4 points */
polygon(0% 0%, 100% 0%, 100% 100%, 0% 100%)

Hover Reveal Effect

A card image that clips to a circle on hover:

.card-img {
  clip-path: inset(0 round 8px);
  transition: clip-path 400ms cubic-bezier(0.4, 0, 0.2, 1);
}

.card:hover .card-img {
  clip-path: circle(50% at 50% 50%);
}

Wipe Transitions

Diagonal wipe transition for page changes:

@keyframes wipe-in {
  from { clip-path: polygon(0 0, 0 0, 0 100%, 0 100%); }
  to   { clip-path: polygon(0 0, 100% 0, 100% 100%, 0 100%); }
}

.page-enter {
  animation: wipe-in 600ms ease both;
}

Performance of clip-path Animation

Animated clip-path triggers the paint stage on most browsers (unlike transform/opacity which are composite-only). For complex animations on large elements, test performance in DevTools before shipping.

clip-path vs mask-image for Animation

For complex animated transparency, mask-image with an animated gradient can be more performant than clip-path for simple directional reveals.

Spring Easing with clip-path

Spring-like easing creates organic-feeling reveals:

.reveal {
  clip-path: polygon(0 0, 0 0, 0 100%, 0 100%);
  transition: clip-path 700ms cubic-bezier(0.34, 1.56, 0.64, 1);
}

Quick Check

What is required for CSS to smoothly interpolate between two polygon() clip-path values?

Recap

Animate between clip-path shapes using transitions or @keyframes. The same shape function with the same number of vertices is required for interpolation. Use circle() for expanding reveals, polygon() for wipes and morphs, and inset() for rectangular clip transitions. Match vertex counts by adding coincident points to simpler shapes.

Frequently asked questions

Is the “Animating clip-path Shapes” lesson free?

Yes — the full text of “Animating clip-path Shapes” is free to read here on the web, and the CSS Academy course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the CSS Academy course, upgrade to CoddyKit PRO.

What will I learn in “Animating clip-path Shapes”?

Create dramatic reveal animations by transitioning between clip-path polygon values. You practise CSS Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start CSS Academy?

No prior experience is required. CSS Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 3 of 4, so you can start here or from the beginning and move at your own pace.

How long does the “Animating clip-path Shapes” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this CSS Academy lesson?

Yes. Every CSS Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

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