Squash and Stretch: The Animation Principle Explained

What is squash and stretch?

Squash and stretch is the deliberate deformation of a shape as it moves — flattening it when it compresses or lands, and elongating it when it accelerates or stretches out. It is the most important of the classic principles of animation, because it is what gives drawn objects the appearance of weight, flexibility and life.

A ball that keeps a perfect circle as it hits the ground looks stiff and lifeless. The same ball squashed slightly on impact and stretched as it launches back up suddenly feels physical — like it has mass and is made of something real.

The golden rule: preserve volume

There is one rule that makes or breaks squash and stretch: volume must stay constant. When a shape squashes and gets shorter, it must get wider to compensate. When it stretches and gets taller, it must get thinner. If the volume visibly grows or shrinks, the object looks like it is inflating or deflating rather than deforming.

Why it makes motion better

Squash and stretch does several jobs at once:

• Conveys weight. How much a shape squashes on impact tells the viewer how heavy and how firm it is.
• Adds life. Rigid shapes read as mechanical; deforming shapes read as organic and alive.
• Smooths fast motion. A stretched shape bridges the gap between frames, so quick movements flow instead of strobing — an idea connected to spacing in the timing and FPS guide.
• Sells impact. A hard squash on a landing makes the moment of contact feel forceful and satisfying.

Flexibility and material

The amount of squash and stretch is a storytelling choice that communicates what something is made of. A rubber ball deforms dramatically. A tennis ball deforms a little. A bowling ball barely deforms at all. By dialling the exaggeration up or down, you tell the viewer the material and firmness of your object without a single word.

The same logic applies to characters. A bouncy, cartoony character squashes and stretches freely; a heavy, serious one moves with far more restraint. Consistency matters: an object should keep the same degree of flexibility throughout a shot, or it will feel like its material is changing.

Squash and stretch on a bouncing ball

The bouncing ball is the classic exercise for this principle because it puts every part of it on display in a few frames:

1. 1
   Falling

   As the ball accelerates downward it stretches slightly along its direction of travel, staying thin and tall.
2. 2
   Contact

   At the moment it hits the ground it squashes — wide and flat — showing the force of impact. This is the single most important frame.
3. 3
   Rebound

   Launching back up, it stretches again as it gains speed, then eases back to a neutral shape near the top of the arc.

Notice that the ball is only its neutral round shape for a moment near the peak, where it is moving slowly. The full walkthrough — including timing and spacing — is in the bouncing ball tutorial, and you can watch it loop on the examples page.

Smears: stretch taken further

A smear frame is stretch pushed to an extreme for a single frame of very fast motion. Instead of a crisp shape, you draw an elongated, blurred, or multiplied form that spans the whole distance the object travels in that frame. On screen it flashes past too quickly to look strange, and it makes rapid motion feel fluid instead of choppy.

Smears are a practical fix for the strobing problem: when spacing is too wide for your frame rate, a smear bridges the gap that a normal drawing cannot. Use them for whip-fast actions — a punch, a head turn, a quick gesture — then return to solid shapes as the motion settles.

Where to use it — and where not to

Squash and stretch shines on impacts, jumps, bounces, facial expressions and any bouncy, energetic motion. It is less appropriate for rigid objects that should not deform — a metal robot, a wooden crate, a brick. Applying it everywhere drains its impact; the principle works best as an accent on the moments that matter most.

Trying it in FrameAnim

FrameAnim's drawing tools and timeline make squash and stretch easy to experiment with. Draw your neutral shape, then on the impact frame redraw it wider and shorter; on the fast frames redraw it taller and thinner. Onion skinning helps enormously here — with the neighbouring frames ghosted underneath, you can keep the widths and heights compensating correctly so volume stays constant. Learn the feature in the onion skinning guide.

Common mistakes

• Changing the volume. The number one error. If the shape gets bigger or smaller overall, it looks like it is inflating, not deforming.
• Squashing in the wrong direction. A shape squashes perpendicular to the force and stretches along its direction of travel. Get this backwards and it looks wrong instantly.
• Overusing it. Constant squashing everywhere becomes exhausting and cheap. Save the strong poses for impacts and accents.
• Inconsistent flexibility. If an object is rubbery in one shot and rigid in the next, its material seems to change. Pick a level of flex and stick to it.

Master this principle and almost everything else improves, because squash and stretch is woven into bounces, walks, jumps and expressions alike. Put it into practice with the bouncing ball exercise next.