animation
Squash and stretch in stop motion
Timing, spacing and arcs in stop-motion animation / Stop motion
Definition
Squash and stretch is the animation principle of deforming a form -- flattening it on impact, elongating it in fast motion -- to convey weight, flexibility and force. In stop motion, which photographs physical objects frame by frame, the deformation has to exist physically under the camera: it is achieved either by resculpting a malleable material such as plasticine between frames, or by swapping in pre-made replacement shapes, and rigid puppets often cannot do it at all.
Overview
Squash and stretch is the first of the classic animation principles, and in drawn or computer animation it is almost free: a ball flattens on impact and elongates as it falls because the artist simply draws or deforms it that way. Stop motion has no such freedom. Most of what an animator moves between frames is solid -- a cast silicone body over a metal armature, a resin face, a carved wooden head -- and solids hold their shape. That is the real subject of this page: not what squash and stretch is, but what a stop-motion production has to physically build or give up in order to get it.
There are two honest answers, and supplier Animation Supplies frames the choice for plasticine plainly: either "a lot of resculpting" or the use of replacements. Resculpting is the clay animator's native route. Because plasticine is reformed by hand between exposures (see clay animation), a character can be pushed flatter on a landing and pulled longer on a leap without any extra parts. The cost is control: every deformation has to return to the same character, and the same guide warns that keeping the design consistent through the distortion is what stops the audience losing track of who they are watching. The second route is replacement: sculpt the extreme shapes in advance and swap them in frame by frame, the method George Pal's Puppetoons used with carved wooden figures in the 1940s (see replacement animation).
Ken A. Priebe's first-person account in The Advanced Art of Stop-Motion Animation shows the trade-off in miniature. Asked to turn Steve Stanchfield's very rubbery, hand-drawn Thunderbean Animation logo into stop motion, Priebe concluded it needed replacement puppets "much like the George Pal Puppetoons" -- a closed pose, a slight squash, a severe squashed anticipation, a big stretch, a transition and a rest -- with Styrofoam cores under clay to keep each shape consistent and light. He reused basic shapes rather than sculpting every pose, and still took the puppet apart between most frames, bending its taped aluminium-wire limbs into new positions, with a helping-hand rig digitally removed afterwards. The lesson is that squash and stretch in stop motion is a design decision made before the shoot, not a flourish added during it.
That is also why restraint matters more here than in other media. Every extreme pose is a physical object or a fresh sculpt, so a production spends its distortions where they carry weight and impact -- a landing, a recoil, an anticipation -- and lets solid puppets read weight through timing and spacing instead. Animation Supplies' caution that too much squash and stretch makes a character read as merely comic is, in stop motion, also a budget note.
Workflow
- Decide which route the character's build allows: resculpt (plasticine body), replace (pre-sculpted shapes or faces), or neither (rigid puppet -- sell weight through timing and spacing instead).
- Thumbnail the action and mark only the frames that truly need distortion: the squash on impact, the anticipation before a leap, the stretch in the fastest part of the move.
- For replacements, sculpt the extreme shapes before the shoot, matching volume and registration so each swap reads as the same character; reuse shapes wherever the action repeats.
- For resculpting, check the silhouette against the neutral model (onion skin or a reference image) so the character returns to model after each extreme.
- Plan support: distorted poses are often unstable, so set up a rig or tie-down before the frame and schedule its removal in post.
- Shoot the extremes in context and review at speed -- a squash that lasts too many frames reads as a pose, not an impact.