Stretch & Squash Techniques Every Animator Should Know

Stretch & Squash: Mastering Motion for Lively AnimationStretch and squash (often written “squash and stretch”) is one of the foundational principles of animation. It’s a deceptively simple idea — objects change shape as they move — yet it’s one of the most powerful tools animators have for conveying weight, flexibility, impact, and personality. Mastering stretch and squash transforms stiff movement into performance and gives drawings or 3D rigs a sense of life and physical truth.

What is stretch and squash?

At its core, stretch and squash describes the deformation of an object to reflect motion and force. When an object accelerates, it may elongate (stretch). When it collides or compresses, it may flatten (squash). Importantly, the volume of the object is commonly preserved: as it squashes, it should widen in the perpendicular axis; as it stretches, it should narrow. This conservation of volume helps maintain believability.

Why it matters

• Conveys weight and mass: A heavy ball should show a pronounced squash on impact and less stretch during flight than a light rubber ball.
• Expresses material and elasticity: Hard objects deform little; soft objects deform more.
• Communicates speed and force: Longer stretches imply faster motion or stronger forces.
• Enhances character and personality: Characters feel more alive when faces, limbs, or bodies subtly exaggerate movement.
• Improves readability: Exaggerated deformations help the audience read motion and intent at a glance.

Key principles and guidelines

1. Preserve volume: when squashing one axis, compensate by expanding the other axis to keep the object’s apparent mass consistent.
2. Respect material: decide how much deformation suits the material (steel vs. rubber vs. flesh).
3. Use squash early and often: apply it not only on extreme poses like impact but in subtle anticipation and follow-through.
4. Pair with timing and spacing: stretch works best when combined with fast timing; squash often happens on strong contact or pause frames.
5. Maintain silhouette clarity: even when deformed, the object’s silhouette should read clearly to avoid visual confusion.
6. Gradual transitions: ease into and out of deformations so the motion feels organic, unless a jarring effect is desired.
7. Limit on faces/complex forms: for characters, facial squash/stretch should be measured—overuse can look cartoony unless that’s the goal.

Practical techniques

• Keyframe exaggeration: pick key poses where stretch or squash is strongest (e.g., anticipation, impact). Draw or pose exaggerated extremes, then use in-betweens to smooth.
• Squash at contact: for bouncing or impacting objects, place the strongest squash on the contact frame, then stretch before (anticipation) and after (rebound).
• Stretch during speed lines: for fast motion, elongate the object along the motion vector; combine with motion blur in digital work.
• Secondary stretch: apply smaller stretches to secondary parts (hair, clothing, tails) to sell momentum.
• Frame-by-frame vs. rig deformation: 2D animators hand-draw squash/stretch; 3D animators use rig controls or blend shapes. In 3D, add corrective shapes to maintain volume and avoid interpenetration.
• Shape keys and corrective blendshapes: pre-build squash/smear blendshapes for faces and bodies to keep topology clean during deformation.
• Smears and motion lines: use one-frame smears (elongated drawings) to emphasize extreme speed; these are a form of stretch used for stylistic effect.

Examples and applications

• Bouncing ball: the classic demonstration. A ball stretches during fast descent, squashes on contact, then stretches again as it rebounds. Adjust the amount by material.
• Character jump: the torso stretches in the leap phase, limbs extend; on landing the body squashes slightly and knees absorb the impact.
• Facial acting: eyelids, cheeks, and mouths can stretch or squash to exaggerate expression—use subtly for realism, strongly for stylized cartoons.
• Cloth and hair: follow-through pieces should squash/stretch slightly to reflect inertia and elasticity.
• Mechanical rigs: even robots can exhibit limited squash to make movement feel warm and alive; use controlled, subtle deformation.

Common mistakes and how to fix them

• Overdoing volume loss: if an object looks like it’s melting, re-balance axes to restore apparent volume.
• Using stretch as a shortcut for sloppy motion: stretch should supplement good timing and mechanics, not replace them.
• Forgetting context: a heavy character should not have the same squash amounts as a rubbery creature. Study reference.
• Breaking silhouette: ensure the deformation still reads; refine extremes to preserve clarity.
• Ignoring secondary motion: if only the primary mass deforms, the shot can feel disconnected—animate secondary parts to match.

Tests and exercises

• Bouncing ball series: animate balls of different materials (metal, rubber, clay) and compare squash/stretch amounts.
• Walk cycle with exaggeration: create a walk where the torso and hips subtly squash and stretch each step.
• Facial phonetics: animate a short line of dialogue emphasizing mouth squash/stretch for vowels.
• One-frame smear practice: animate a fast whip or punch using single-frame smears to sell speed.

Tips for 2D vs 3D

2D:

• Hand-draw extreme shapes and in-betweens.
• Use smears and elongated frames for speed.
• Maintain appealing line quality through deformation.

3D:

• Build stretch/squash controls in the rig (global scale, squash controllers, blendshapes).
• Use corrective blendshapes to avoid collapsing geometry.
• Animate pivot points and joint influences carefully so limbs deform believably.
• Consider motion blur and shader-driven stretch for added realism.

When to avoid strong stretch & squash

• Photorealistic, rigid materials where deformation breaks suspension of disbelief.
• Subtle, dramatic scenes where exaggerated motion would reduce emotional impact.
• Technical shots where collision accuracy matters more than stylistic deformation.

Resources to study

• Classic Disney animation books and Ollie Johnston & Frank Thomas’s “The Illusion of Life” for foundational theory.
• Animation exercises and breakdowns of bouncing balls and walk cycles.
• Rigging tutorials for squash-and-stretch controls in Maya/Blender and blendshape workflows.
• Study real-world reference: slow-motion footage of impacts, elastic materials, and animals.

Quick checklist before finishing a shot

• Does deformation support the material and weight?
• Is volume visually consistent across the squash/stretch?
• Are silhouettes readable when deformed?
• Are secondary parts following or opposing movement to sell inertia?
• Have you paired deformations with timing, easing, and motion blur where needed?

Stretch and squash is both a physical law of convincing motion and a stylistic lever. Used thoughtfully, it turns motion into language — conveying force, mood, and character with a single, elegant idea.