Animal gaits

1. A gait is a footfall order plus a flight phase. Walk: four beats in lateral sequence, 2–3 feet always down. Trot: two beats, diagonal pairs, flight between. Canter: three beats with a lead, flight after. Gallop: four beats, then a long flight. Pick the gait first; the poses follow from the chart below.
2. Walk order: near hind → near fore → far hind → far fore. Each foot lands a quarter-cycle after the previous one; after a fore foot the diagonal hind lands next. Decision: Williams's "front leg twins with the opposite back leg" is his own comic donkey walk, not the animal's, and Saint11's "trot" demo lands one foot every two frames in walk order. Use the lateral order for walks and diagonal pairs only for trots; keep the wrong order for drunk, dying or puppet animals (Thomas & Johnston).
3. Model it as two bipeds with a time offset. Hind pair and front pair each walk like a two-legged walk; the front pair is one quarter-cycle behind the hind pair on the same side. Draw one near leg through the whole cycle, copy it to the far leg shifted by half a cycle, then do the other pair at a quarter-cycle offset (rules://06-layers-and-rigging).
4. Front and hind paws travel the same distance. If the front stride is longer than the hind stride the body stretches and shrinks like an accordion. The sweep of a planted paw against the body is about 0.5 H (6 px at H = 12 in the templates); the body advances about 1 H per full cycle at a walk (Goldfinger's estimate, not measured).
5. A planted paw must move back at the ground speed. Body advance per cycle = sweep × frames ÷ stance frames. Sweep 6 px, 8 frames, 5 stance frames → 9.6 px per cycle, i.e. 1.2 px per frame (derived). Any other engine speed and the feet skate.
6. Leg cycle: contact → drag → rise → swing. The paw is planted and slides back relative to the body (drag), lifts, then arcs forward and drops. The swing foot follows an arc, never a straight slide: lift ≈ 25–30 % of leg length (Hultgren, deer), 1–2 px at H = 12, 2–3 px at H = 20.
7. Joints move in a fixed pattern. Front leg: shoulder swings steadily, the elbow moves fast at contact and release, the paw snaps at release. Hind leg: hip steady, the stifle lifts the foot, the paw lags. Stifle and hock fold together (never flex one without the other in the same frame); the fetlock folds with the carpus; the carpus folds backward, the hock folds the foot up toward the buttock.
8. Flex ranges for clamps (horse plates, ±10–15 %): elbow 150° → 35°, carpus 180° → 30°, stifle 130° → 50°, hock 150° → 40°, hip 120° flexed → 170° extended. A joint outside its range is a pose the animal cannot make.
9. Weight moves the spine. Williams's two dog extremes: A, pelvis up on the hind pass while the chest drops on the front contact; B, pelvis down on the hind contact while the chest and shoulders rise. Shoulders and hips tilt opposite ways by 1 px each step. Bob (peak to peak): 1 px up to 24 px wide, 2 px at 32, 3 px at 64 (derived from Williams, Blair).
10. Head and tail are late. Head 1 frame behind the chest; the nose follows the chest up and down. Tail and ears lag 1–2 frames with decaying swing (3, 2, 1 px) on their own layers (rules://45-secondary-motion).
11. Trot: diagonal pairs and a flight. Near fore + far hind land together, then near hind + far fore. Between pairs every foot is off the ground for 1 frame (8-frame loop); the body is 1 px higher in flight and 1 px lower at contact (derived). No flight frame is acceptable at 16 px.
12. Canter: three beats and a lead. One hind alone, then the other hind with its diagonal fore, then the leading fore, then flight. The leading fore reaches farthest. The body rocks forward and back along a rolling wave; the head nods on each beat.
13. Gallop: two extremes. Extended: spine flat, fore legs reaching forward, hind legs thrown back, belly raised 1–2 px, torso 10–15 % longer (dog, cat, cheetah; horses and cattle stay the same length). Gathered: spine arched, all four feet bunched under the belly. Decision: photographs show the flight phase gathered, cartoon charts show it stretched (Blair). Use the gathered pose for realism and the stretched one for cartoon speed; in both, keep one frame near contact with a foot down.
14. Heavy animals bounce less. Bears, bulldogs, rhinos: low bounce, large head swing, squash on landing, long contact holds (Blair). Light animals (cats, deer, rabbits) get higher arcs.
15. Cycles must not look like cycles. Loop the legs on the cycle length, but give the tail, head or mane a different period (legs 8 frames, tail 12) so the repeat disappears. The last frame must lead into the first.
16. Sneak and sprint are walks with different holds. Sneak: body low, belly 1–2 px from the ground, contact frames held 1.5–2× longer, other frames fast. Sprint: trot or gallop with the stride lengthened, not the frame rate raised.

Eight time steps per stride; # = foot on the ground. Schematic (derived from published footfall sequences), not measured. NH near hind, NF near fore, FH far hind, FF far fore.

WALK                          TROT                           CANTER (far hind leads)
     0 1 2 3 4 5 6 7               0 1 2 3 4 5 6 7                0 1 2 3 4 5 6 7
NH   # # # # # . . .          NF   # # # . . . . .           FH   # # . . . . . .
NF   . . # # # # # .          FH   # # # . . . . .           NH   . . # # . . . .
FH   # . . . # # # #          NH   . . . . # # # .           FF   . . # # . . . .
FF   # # # . . . # #          FF   . . . . # # # .           NF   . . . . # # . .
feet down 3,2,3,2,3,2,3,2     flight at 3 and 7              flight at 6 and 7

GALLOP (4 beats)
     0 1 2 3 4 5 6 7
FH   # # . . . . . .
NH   . # # . . . . .
FF   . . # # . . . .
NF   . . . # # . . .
flight at 5, 6, 7

Frame mapping: an 8-frame walk puts a foot contact on frames 0, 2, 4, 6 (NH, NF, FH, FF); frames 1, 3, 5, 7 are the passings. A 4-frame walk is exactly those four contacts at 150–170 ms; add the passings when you have room.

Hold the contact frames 20–40 ms longer than the passings and the gather frame 1 tick longer than the extend frame; never use one duration for the whole cycle (rules://05-animation). A fast gait raises the step rate, it does not shrink the frames below 50 ms.

Four contact frames of an 8-frame walk. Same dog and same body in every frame, far legs one ramp step darker; the 1 px bob (chest up, pelvis down on the hind contacts, the reverse on the fore contacts) and the late head are added per frame in the animation, not baked into these key poses. Frame 1: near hind lands; frame 2: near fore; frame 3: far hind; frame 4: far fore. Each leg is one articulated chain (upper segment, bent middle joint, paw); the planted paws touch the same ground row. Paste each into its own frame and fill the passings between them.

O = outline        #2b1d2e
B = coat           #b9824f
L = coat-light     #e0b07a
E = eye            #ffffff
N = nose           #1a1216
M = tail-dark      #5a3a2a
S = coat-shadow    #8a5a3a
F = far-leg        #6e4630
---
......O.........................
.....OBO........................
.....OBBO.......................
....OOBBBO......................
...OBBBBBO......................
....OBBBBLO.....................
.OOOOBBBBBOOOOOOOOO.......OO....
ONBBBBEBBBLLLLLLLLLOOOOO.OMMO...
OBBBBBBBBBBBBBBBBBBLLLLLO.OOMO..
.OOOOBBBBBBBBBBBBBBBBBBBLO.OMO..
.....OOBBBBBBBBBBBBBBBBBBLOOMO..
.......OBBBBBBBBBBBBBBBBBBLOMO..
.......OSBBBBBBBBBBBBBBBBBBOMO..
........OBBBBSSSSSSSBBBBBBBOO...
........OBBBBSSSSSSBBBBBBBBO....
........OBBSOOOOOOOBBSOFFOO.....
........OBBBSOO...OSBSOFFFO.....
.........OOBBBSOOO.OBBSOFFO.....
........OFFOBBBSSSO.OBSOFFFO....
........OFFOOOOOOO..OSSOOFFO....
........OFFO........OBSOOFFO....
........OFFO........OBSOOFFO....
.......OFFFO.......OSSSOOFFFO...
........OOO.........OOO..OOO....

O = outline        #2b1d2e
B = coat           #b9824f
L = coat-light     #e0b07a
E = eye            #ffffff
N = nose           #1a1216
M = tail-dark      #5a3a2a
S = coat-shadow    #8a5a3a
F = far-leg        #6e4630
---
......O.........................
.....OBO........................
.....OBBO.......................
....OOBBBO......................
...OBBBBBO......................
....OBBBBLO.....................
.OOOOBBBBBOOOOOOOOO.......OO....
ONBBBBEBBBLLLLLLLLLOOOOO.OMMO...
OBBBBBBBBBBBBBBBBBBLLLLLO.OOMO..
.OOOOBBBBBBBBBBBBBBBBBBBBO.OMO..
.....OOBBBBBBBBBBBBBBBBBBLOOMO..
.......OBBBBBBBBBBBBBBBBBBLOMO..
.......OSBBBBBBBBBBBBBBBBBBOMO..
.......OBBBBBSSSSSSSSBBBBBBOO...
.......OBBBBBSSSSSSBBBBBBBBO....
.......OBSOFFOOOOOOOSBSOOOO.....
......OSBSOFFO......OBBSO.......
......OBSOOFFO.....OFOBBSOO.....
......OBSOOFFFO.....OFOBSOFO....
.....OBSO..OFFO......OOBSOFO....
.....OBSO..OFFO.......OSSOO.....
.....OBSO...OFFO......OSSOFO....
....OSSSO..OFFFO......OSSSO.....
.....OOO....OOO........OOO......

O = outline        #2b1d2e
B = coat           #b9824f
L = coat-light     #e0b07a
E = eye            #ffffff
N = nose           #1a1216
M = tail-dark      #5a3a2a
S = coat-shadow    #8a5a3a
F = far-leg        #6e4630
---
......O.........................
.....OBO........................
.....OBBO.......................
....OOBBBO......................
...OBBBBBO......................
....OBBBBLO.....................
.OOOOBBBBBOOOOOOOOO.......OO....
ONBBBBEBBBLLLLLLLLLOOOOOOOMMO...
OBBBBBBBBBBBBBBBBBBLLLBBBOOOMO..
.OOOOBBBBBBBBBBBBBBBBBBBBO.OMO..
.....OOBBBBBBBBBBBBBBBBBBLOOMO..
.......OBBBBBBBBBBBBBBBBBBLOMO..
.......OSBBBBBBBBBBBBBBBBBBOMO..
........OBBBBSSSSSSSSSBBBBBOO...
........OBBBBSSSSSSBBBBBBBBO....
........OBSOOOOOOOOFFOBBSOO.....
........OBSOFOO...OFFFOBBSO.....
........OBSOFFFOOO.OFFOBBSO.....
........OBSOFFFFFFO.OFFOBBSO....
........OBSOOOOOOO..OFFOOBSO....
........OBSO........OFFOOBSO....
........OBSO........OFFOOBSO....
.......OSSSO.......OFFFOOSSSO...
........OOO.........OOO..OOO....

O = outline        #2b1d2e
B = coat           #b9824f
L = coat-light     #e0b07a
E = eye            #ffffff
N = nose           #1a1216
M = tail-dark      #5a3a2a
S = coat-shadow    #8a5a3a
F = far-leg        #6e4630
---
......O.........................
.....OBO........................
.....OBBO.......................
....OOBBBO......................
...OBBBBBO......................
....OBBBBLO.....................
.OOOOBBBBBOOOOOOOOO.......OO....
ONBBBBEBBBLLLLLLLLLOOOOO.OMMO...
OBBBBBBBBBBBBBBBBBBLLLLLO.OOMO..
.OOOOBBBBBBBBBBBBBBBBBBBLO.OMO..
.....OOBBBBBBBBBBBBBBBBBBLOOMO..
.......OBBBBBBBBBBBBBBBBBBLOMO..
.......OSBBBBBBBBBBBBBBBBBBOMO..
........OBBBBSSSSSSSSBBBBBBOO...
........OBBBBSSSSSSBBBBBBBBO....
.......OFOBBSOOOOOOOOBBSOOO.....
......OFFFOBSO.....OSBBSOO......
......OFFOOBSO.....OBSBBBSO.....
......OFFOOBBSO.....OBSBBBSO....
.....OFFO..OBSO......OOOOBSO....
.....OFFO..OBSO........OBSO.....
.....OFFO...OBSO.......OSSSO....
....OFFFO..OSSSO......OFOOO.....
.....OOO....OOO........O........

Trot: gait-trot-contact is a diagonal pair (near fore, far hind) planted at mid-stance; gait-trot-flight is the one-frame flight with all four paws off the ground and the body 1 px higher. Mirror the pair for the second half-cycle.

O = outline        #2b1d2e
B = coat           #b9824f
L = coat-light     #e0b07a
E = eye            #ffffff
N = nose           #1a1216
M = tail-dark      #5a3a2a
S = coat-shadow    #8a5a3a
F = far-leg        #6e4630
---
................................
......O.........................
.....OBO........................
.....OBBO.......................
....OOBBBO......................
...OBBBBBO......................
....OBBBBLO.....................
.OOOOBBBBBOOOOOOOOO.......OO....
ONBBBBEBBBLLLLLLLLLOOOOO.OMMO...
OBBBBBBBBBBBBBBBBBBLLLLLO.OOMO..
.OOOOBBBBBBBBBBBBBBBBBBBLO.OMO..
.....OOBBBBBBBBBBBBBBBBBBLOOMO..
.......OBBBBBBBBBBBBBBBBBBLOMO..
.......OSBBBBBBBBBBBBBBBBBBOMO..
........OBBBBSSSSSSSSBBBBBBOO...
........OBBBBSSSSSSBBBBBBBBO....
........OBBSOOOOOOOOBBBSOOO.....
........OBSOFOOOO..OSBBBBSO.....
........OSSOFFFFFO.OBSBBBSO.....
........OBSOOFFFFFO.OOOOBSO.....
........OBSO.OOOOO....OSSO......
........OBSO..........OSSSO.....
........OBSO...........OOO......
........OSSSO.........OFFFO.....
.........OOO...........OOO......

O = outline        #2b1d2e
B = coat           #b9824f
L = coat-light     #e0b07a
E = eye            #ffffff
N = nose           #1a1216
M = tail-dark      #5a3a2a
S = coat-shadow    #8a5a3a
F = far-leg        #6e4630
---
......O.........................
.....OBO........................
.....OBBO.......................
....OOBBBO......................
...OBBBBBO......................
....OBBBBLO.....................
.OOOOBBBBBOOOOOOOOO.......OO....
ONBBBBEBBBLLLLLLLLLOOOOO.OMMO...
OBBBBBBBBBBBBBBBBBBLLLLLO.OOMO..
.OOOOBBBBBBBBBBBBBBBBBBBLO.OMO..
.....OOBBBBBBBBBBBBBBBBBBLOOMO..
.......OBBBBBBBBBBBBBBBBBBLOMO..
.......OSBBBBBBBBBBBBBBBBBBOMO..
........OBBBBSSSSSSSBBBBBBBOO...
........OBBBBSSSSSSBBBBBBBBO....
.......OFOBBSOOOOOOBBSSOFFO.....
......OFFFOBBSO...OBBSOFFFO.....
......OFFFOOBSO...OSBBSOFFO.....
......OFFO.OBBSO...OBBSOFFO.....
......OFFO..OBBSO...OBBSOFFO....
......OFFO...OBBSO...OBSOFFO....
......OFFO...OSSSO..OBSOOFFO....
.....OFFFO....OOO...OBSO.OFFO...
......OOO...........OSSSOOFFO...
.....................OOO.OFFFO..

Gallop: gait-gallop-extend is the flat stretched pose; gait-gallop-gather is the arched pose with the feet bunched under the belly. Alternate them; add one contact frame between with a hind foot down.

O = outline        #2b1d2e
B = coat           #b9824f
L = coat-light     #e0b07a
E = eye            #ffffff
N = nose           #1a1216
M = tail-dark      #5a3a2a
S = coat-shadow    #8a5a3a
F = far-leg        #6e4630
---
..........O...........................
.........OBO..........................
.........OBBO.........................
........OOBBBO........................
.......OBBBBBO........................
........OBBBBLO.......................
.....OOOOBBBBBOOOOOOOOO.......OO......
....ONBBBBEBBBLLLLLLLLLOOOOO.OMMO.....
....OBBBBBBBBBBBBBBBBBBLLLLLO.OOMO....
.....OOOOBBBBBBBBBBBBBBBBBBBLO.OMO....
.........OOBBBBBBBBBBBBBBBBBBLOOMO....
...........OBBBBBBBBBBBBBBBBBBLOMO....
.......OOOOBBBBBBBBBBBBBBBBBBBBOMO....
.....OOBBBBBBBBBBSSSSSSSSSBBBBBOO.....
...OOBBBBBBBBBBBBSSSSSSBBBBBBBBBO.....
..OSSSSOOOOOOFOOOOOOOOOOOOOOBBBBSO....
...OOOO.OFFFFO............OFOBBBBSOO..
.......OFFFOO..............OFOOBBBBSOO
.......OFFO................OFFFOOBBBBS
......OFFO..................OFFFOOOOSS
.....OFFFO...................OFFFOO.OO
......OOO.....................OFFFFO..
...............................OOFFFO.
.................................OOO..
......................................
......................................

O = outline        #2b1d2e
B = coat           #b9824f
L = coat-light     #e0b07a
M = tail-dark      #5a3a2a
E = eye            #ffffff
N = nose           #1a1216
F = far-leg        #6e4630
S = coat-shadow    #8a5a3a
---
......................................
..........OO..........................
.........OBBO.........................
.........OBBBO........................
........OOBBBO........................
.......OBBBBBLO.......................
........OBBBBBOOOOOOOOO...............
.....OOOOBBBBBLLLLLLLLLOOOOO..OO......
....ONBBBBEBBBBBBBBBBBBLLLLLOOMMO.....
....OBBBBBBBBBBBBBBBBBBBBBBBO.OOMO....
.....OOOOBBBBBBBBBBBBBBBBBBBLO.OMO....
.........OOOBBBBBBBBBBBBBBBBBLOOMO....
...........OSBBBBBBBBBBBBBBBBBLOMO....
............OBBBBSSSSSSSBBBBBBBOMO....
...........OBBBBBSSSSSBBBBBBBBBOO.....
..........OBBBBOOOOOOOBBBBBBBBBO......
..........OBSSOO.....OSBBBBSOOO.......
...........OSSOFO..O..OOOBBSO.........
...........OBSOOO.OFO...OBSOO.........
............OBSBSOFFFO.OSSSOFO........
............OBBSSSOOO...OOOFFO........
.............OOOOO.......OFFO.........
........................OFFFO.........
.........................OOO..........
......................................
......................................

1. Choose the gait and the frame count from the By size and Timing tables. Write the stance windows from the footfall chart for each leg.
2. Rig the animal on layers: tail, leg-far-hind, leg-far-front, body, head, leg-near-hind, leg-near-front (layer op create with a batch).
3. frame op add for the full frame count. Draw the near hind leg on every frame: contact, drag, rise, swing, with the stifle and hock folding together. Use the body with its bob only as a guide.
4. Copy the near hind leg to leg-far-hind and rotate the frames by half a cycle (cel op copy then move). Draw the near front leg and copy it to leg-far-front the same way. Offset the front pair by a quarter cycle from the hind pair.
5. Move the body per frame: pelvis and chest by their offsets (rule 9), head one frame late, tail and ears with delay and decay. Do this with cel op move, not by redrawing.
6. look op filmstrip: are 2–3 feet down on every walk frame, are the contacts evenly spaced, does the silhouette change between consecutive frames by at least 2 px somewhere? look op onion on each passing: the swing foot should clear the ground in an arc.
7. frame op set_duration with the ms array from Timing, tag the cycle (walk, trot, gallop), loop check: does the last frame lead into the first? validate for timing and orphan pixels.

• Sliding → paw does not move back at ground speed → apply rule 5 or lengthen the stance.
• Rowing (front and hind legs together in pairs on a walk) → pairs instead of the lateral order → rule 2; reserve pairs for the trot.
• Accordion body → front and hind strides differ, or the spine length drifts → equal strides, keep the torso length constant except in a gallop.
• Rubber hind leg → stifle folds without the hock, or the lower leg changes length → rule 7 and rule 8; segment lengths stay fixed to ±1 px.
• Everything moves at once → body, head and tail on the same beat → head 1 frame late, tail 1–2 frames late, different period for the mane.
• No weight → body flat on the walk → add the pelvis/chest alternation of rule 9.
• Gallop that only stretches → no gathered frame → alternate extend and gather, do not just widen the legs.
• A hovering walk → fewer than 2 feet down at some frame → check the stance windows.
• Uniform timing → every frame 100 ms → vary hold lengths per Timing.

• Footfall order matches the gait: walk lateral, trot diagonal, gallop four separate beats.
• At least 2 feet down on every walk frame; flight frames exist where the gait has them.
• Paw speed on the ground equals the engine's body speed; no skating.
• Stifle and hock fold together; no joint outside the flex ranges; segment lengths constant.
• Body bob and spine alternate with the legs; head and tail are one to two frames late.
• Far legs darker and behind; no tangents between near and far legs.
• Frame durations vary; the cycle is tagged and loops cleanly (rules://07-review-checklist).

• Richard Williams, The Animator's Survival Kit, pp. 327–332 (animal walks, dog 20-frame chart, donkey gag walk, corrected contact order).
• Frank Thomas and Ollie Johnston, The Illusion of Life: footfall rule and where legs squash and stretch, PDF pp. 355–358.
• Preston Blair, Advanced Animation, p. 25 (walk, trot, canter, gallop on a grid), p. 9 (heavy animals).
• Ken Hultgren, The Art of Animal Drawing, pp. 34–37, 53–54, 71, 97 (trot, canter, deer walk, cat leap, greyhound).
• Eliot Goldfinger, Animal Anatomy for Artists, pp. 20–25 (joint motion plates).
• Pedro Medeiros (Saint11), 4LegsWalk tutorial (16 frames at 100 ms); Slynyrd, Pixelblog 25 (Shiba walk, 8 frames).
• Footfall sequences of the horse gaits and the 11-frame gallop sheet from the Liberated Pixel Cup horse (Muybridge-based).