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Lesson 2 of 7Animation & Special Effects
Unit 2 · Lesson 2 of 7

Animation Methods: Frame-by-Frame, Stop-Motion, Cut-Out and Rotoscoping

Four ways of producing the frames of an animation, the equipment each one needs, and how shooting on ones or twos changes the number of drawings or poses you have to make.

5 min read11 practice questionsAsk AI about this →

Key things to remember

  1. 1Frame-by-frame draws every image; stop-motion photographs a physical object moved slightly; cut-out reposes jointed flat parts; rotoscoping traces live-action footage.
  2. 2Stop-motion needs a locked-off camera, manual exposure, focus and white balance, and controlled light, or the film jumps and flickers.
  3. 3Armatures let a puppet hold a pose; tie-downs and rigs hold it in place or in the air.
  4. 4On ones = a new image every frame; on twos = each image held for 2 frames (12 images per second at 24 fps).
  5. 5
  6. 6Fast action is animated on ones to avoid stutter; slower action is usually on twos to halve the work.

Every animation runs on the same trick: show a sequence of slightly different still images fast enough and the brain sees motion. What separates the methods is where those stills come from. You can draw each one, photograph a physical puppet moved a fraction at a time, slide flat jointed pieces around, or trace over live-action film. Each method has its own look, its own equipment and its own way of going wrong, and choosing well at the start decides how many hours the project will take.

Four methods compared

MethodWhat changes between framesKey equipmentExamples
Frame-by-frame (hand-drawn)A new drawing, on paper or a tabletLight table or onion skinning, peg bar for registrationClassic Disney features; much of the National Film Board of Canada's work
Stop-motionA physical object moved slightly, then photographedLocked-off camera, controlled lights, armatures, capture softwareAardman's Wallace & Gromit; Laika's Coraline
Cut-outFlat jointed pieces repositioned (on paper or as a digital puppet)Pre-cut parts with hinged joints, a top-down camera or puppet softwareTerry Gilliam's Monty Python sequences; South Park
RotoscopingA drawing traced over each frame of live-action footageVideo reference and a drawing layer over itMax Fleischer's rotoscope (1915); A Scanner Darkly

Frame-by-frame drawing

The frame you are drawing, with its neighbours showing throughearlier frames (ghosted)later frames (ghosted)current frametight gaps = slowwidening gaps = speeding upOnion skinning is the only way to judge spacing while you draw a single frame.Even gaps read as constant speed; a cluster of tight gaps reads as a pause or an ease.
Fig 1Onion skinning shows the drawings before and after the current one, so each new drawing can be placed relative to its neighbours.

Hand-drawn animation gives complete freedom: any shape can turn into any other. The cost is that every frame is a drawing. Animators keep it manageable by working pose to pose: first the keys (the storytelling poses), then breakdowns (the poses that decide how the move gets from one key to the next), then in-betweens to fill the gaps. On paper, every sheet sits on a peg bar so the drawings stay in register; on a light table or with digital onion skinning, the animator sees the neighbouring drawings through the current one, which is how arcs and spacing stay consistent.

Stop-motion: the equipment is the technique

  • Locked-off camera. The camera must not move at all between frames. Use a heavy tripod, tape it down, and trigger it from software or a remote. A camera nudged by a millimetre shows as a jump in the finished film.
  • Manual settings. Set exposure, focus and white balance to manual. On auto, the camera re-meters each frame and every small change in the set becomes a flicker of brightness.
  • Controlled light. Shut out daylight, which changes constantly as clouds pass, and use lamps that stay in place. Do not stand where your shadow or clothing reflects onto the set.
  • Armatures. A wire or ball-and-socket skeleton inside a clay or foam puppet lets it hold a pose without drooping between frames.
  • Tie-downs and rigs. Screws or magnets through the feet hold the puppet in place; hidden rigs hold it in the air and are removed later in editing.
  • Capture software with onion skinning, such as Dragonframe or Stop Motion Studio, so each new pose can be compared with the last one before it is shot.
Where flicker comes from
Flicker is the most common stop-motion fault, and it nearly always comes from one of three things: automatic exposure, changing daylight, or the animator's own body blocking or reflecting light. Fix all three before the first frame. Flicker can sometimes be reduced in editing, but it is far easier to prevent.

Cut-out animation trades freedom for speed: a character is built once from jointed flat pieces, then posed rather than redrawn. Digital puppet software works the same way, which is why many TV series use it, and because the same parts are reused in every shot the character always stays on model. Rotoscoping gives realistic, weighty motion because it copies a real performance, but it can look floaty if the animator traces every wobble; the skill is in choosing what to leave out. In visual effects, 'roto' also means tracing a moving object frame by frame to create a matte for compositing.

Shooting on ones, twos and threes

At 24 fps a second of animation has 24 frames, but it does not need 24 different drawings or poses. On ones means a new image every frame. On twos means each image is held for two frames, so 12 new images per second at 24 fps. Twos have been the standard for most hand-drawn and stop-motion work, because they halve the work while still reading as smooth motion. Fast actions, such as a quick head turn or a camera pan, are animated on ones so they do not stutter.

On ones divide by 1, on twos by 2, on threes by 3.
10 seconds at 24 fpsFramesNew images needed
On ones240240
On twos240120
On threes24080
Mix ones and twos within a shot
You do not have to pick one rate for a whole film. Professionals switch within a single shot: twos for a character standing and talking, ones for the fast swing of an arm or a whip pan, then back to twos. Plan it on the exposure sheet before you start, because the drawing count, and therefore the schedule, depends on it. A useful planning habit is to estimate the time per drawing or pose from a short test, then multiply by the count: a 20-second stop-motion scene on twos at 24 fps is 240 poses, and at two minutes per pose that is eight hours of shooting before a single retake.

Worked examples

Reveal one step at a time and try to beat it to the next line.

Example 1
A hand-drawn shot lasts 8 seconds at 24 fps and is animated on twos. How many frames and how many drawings are needed?
Example 2
Plan a 30-second stop-motion film at 24 fps, shot on twos. Test shots show each pose takes about 90 seconds to set up and capture. How long will shooting take?
Example 3
A student's first stop-motion test brightens and darkens randomly from frame to frame, and twice the whole picture jumps sideways. Diagnose and fix it.
Example 4
Choose a method for each project: (a) a music video where a dancer's real performance becomes a flowing line drawing, (b) a 60-second public service announcement due in one week, with one talking character, (c) a short film about a clay creature exploring a kitchen.

Where marks get lost

  • Leaving the camera on automatic exposure for stop-motion, which turns every small change in the scene into flicker.
  • Shooting stop-motion near a window, so changing daylight makes the brightness drift.
  • Animating a fast action on twos, which makes it stutter; quick moves need ones.
  • Calculating drawings from seconds × fps and forgetting to divide by the number of frames each drawing is held.
  • Building a clay puppet with no armature, so it slowly droops between frames and the poses cannot be held.

Flashcards 9

Frame-by-frame animation
Stop-motion
Cut-out animation
Rotoscoping
+ 5 more

Practice

1
A 12-second hand-drawn scene at 24 fps is animated entirely on twos. How many drawings are needed?
drawings
2
A 5-second background loop at 24 fps is animated on threes. How many drawings does it need?
drawings
3
A stop-motion animator shoots 180 poses, and the film plays them on twos at 24 fps. How many seconds long is the film? Give a whole number.
s
4
A stop-motion clip brightens and darkens slightly from frame to frame. What is the most likely cause?
5
What is rotoscoping?
6
Which action should be animated on ones rather than twos?
7
What is the name for the internal wire or ball-and-socket skeleton that lets a stop-motion puppet hold a pose?
8
What is it called when each drawing in an animation is held for two frames?
9
Put the stages of pose-to-pose hand-drawn animation in order.
  1. 1Colour the finished drawings
  2. 2Clean up the rough drawings into final line work
  3. 3Fill in the in-betweens
  4. 4Draw the key poses that tell the story
  5. 5Add breakdown poses that decide how each move travels
10
Match each method to an example of it.
Stop-motion
Cut-out
Rotoscoping
Frame-by-frame drawing
11
Why must the camera be locked off for stop-motion?

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