Skill: Figure Posing & Body Mechanics
What
The animator's vocabulary for describing body positions in text prompts. How to make a character look like they're DOING something — not posed for a photograph. Covers line of action, weight, foreshortening, toddler-specific mechanics, and the Pixar posing principles.
Why
AI models default to stiff, symmetrical, catalog-model poses. Without explicit body language in the prompt, every character stands like a mannequin. Animators and figure artists have a precise vocabulary for describing living, dynamic poses — this skill translates that vocabulary into prompt language. The difference between "a girl standing" and "a girl with weight on her left hip, right knee bent, one hand reaching up, spine in a gentle S-curve" is the difference between dead and alive.
1. Line of Action — The Skeleton of Every Pose
Before writing any character description, decide the dominant body curve. This is the single line that flows from head to feet.
| Line Type | Feel | When to Use | Prompt Fragment |
|---|
| C-curve | Compression, settling, defeat, comfort | Sitting, slumping, curling up, being held | "body curved into a C-shape, [direction]" |
| S-curve | Dynamic, alive, twist, elegance | Walking, turning, dancing, natural standing | "natural S-curve through the spine, hips and shoulders opposing" |
| Straight/I-line | Rigid, tense, power, shock | Military stance, surprise, falling stiff | "body rigid and straight as a board, every muscle taut" |
The more a line bends, the more energy it holds. A long fluid curve = relaxed. Sharp corners = explosive.
Prompt examples:
- "A toddler curled into a tight C-curve on a bed, knees pulled to chest, head tucked down, body forming a compact crescent"
- "A woman in an elegant S-curve, weight on her left hip, shoulders tilted opposite to hips, one hand on waist"
- "A soldier at rigid attention, body a straight vertical line, chin up, arms pressed to sides"
Rule: Decide the line shape BEFORE writing the rest of the pose. Everything else follows from it.
2. Weight Distribution — Where the Mass Sits
| Term | Meaning | Prompt Language |
|---|
| Planted | Weight fully on feet | "weight planted firmly on left foot" |
| Bearing | Limb carrying load | "right arm bearing full weight against wall" |
| Settled | Sunk into surface | "body settled deep into cushion, hips sunk low" |
| Suspended | Hanging from above | "hanging from bar, full weight pulling through arms" |
| Shifted | Weight to one side | "weight shifted onto right hip, left leg relaxed" |
| Toppling | Past balance point | "leaning far forward, weight past the toes, about to fall" |
Center of gravity by action:
| Action | COG Position | Prompt |
|---|
| Standing still | Over feet | "balanced upright, weight centered" |
| Sitting | Over hips | "weight low and settled into the chair" |
| Climbing | Toward handholds | "body pressed close to surface, hips tucked, reaching up" |
| Running | Forward of feet | "torso pitched ahead of the feet, driving forward" |
| Carrying heavy | Away from load | "leaning back to counterbalance, hips thrust forward" |
| Falling | Past support | "center of gravity thrown past feet, arms trailing" |
3. Contrapposto — Making Standing Characters Alive
The body's natural response to standing on one leg. The loaded hip rises, the opposite shoulder drops. This creates an S-curve through the torso. Symmetry = dead. Contrapposto = alive.
The rule: Right hip up → right shoulder down (and vice versa).
Default for any standing character:
"Weight on [left/right] leg, opposite hip dropped, shoulders tilted counter to hips, head tilted slightly [direction], one hand [action], other hanging loose"
Twinning avoidance (Pixar rule): NEVER mirror left and right sides. Different arm positions, different leg angles, head tilted, weight uneven. Symmetrical poses look robotic.
4. Anatomical Landmarks — The Six Pairs
Track these to make any pose readable:
Shoulder Line vs Hip Line (MOST IMPORTANT)
| Relationship | Reads As | Prompt |
|---|
| Parallel, level | Stiff, robotic | "shoulders and hips level, squared" |
| Opposing tilts | Natural, alive | "shoulders tilted left while hips tilt right" |
| Extreme opposition | Dynamic action | "dramatic counter-rotation, shoulder line nearly perpendicular to hip line" |
Head Tilt
- Toward raised shoulder → shy, coy, defensive
- Away from raised shoulder → open, confident
- Forward (chin down) → aggressive, determined
- Back (chin up) → proud, defiant, vulnerable
- Lateral → curiosity, playfulness
Spine Curve
- C-curve forward → slouch, defeat, comfort
- C-curve back (arched) → proud, stretching
- S-curve → dynamic, natural movement
- Straight → military, tense, shocked
Quick Reference: Emotion Through Landmarks
| Emotion | Spine | Head | Hands | Feet |
|---|
| Joy | Arched back | Chin up | Raised, open | Wide or tiptoes |
| Sadness | Deep C forward | Chin to chest | Hanging limp | Close, even |
| Fear | Compressed C | Chin tucked | Defensive, front of body | Close, weight back |
| Anger | Straight/forward | Brow leading | Fists clenched | Wide, weight forward |
| Curiosity | S-curve lean | Tilted to side | One reaching | Weight on front foot |
| Exhaustion | Deep C slump | Hanging | Dangling | Dragging, uneven |
5. Silhouette Test
A pose should communicate its action purely from its outline — as if blacked out.
Rules:
- Arms away from body (not glued to sides)
- Fingers spread or clearly holding objects
- Legs at different angles (not parallel)
- Head turned slightly (dead-center flattens)
- Held objects visible against negative space
Prompt pattern: After writing a pose, mentally black it out. Would you understand the action? If not, push limbs further from the body.
6. Toddler-Specific Mechanics
Proportions (embed in every toddler prompt)
| Feature | Toddler (1-3 years) | Adult |
|---|
| Head:body ratio | 1:4 | 1:7.5 |
| Limbs | Short, chubby, dimpled at joints | Long, proportional |
| Belly | Round, protruding | Flat/varied |
| Legs | Short, slightly bowed | Long, straight |
| Center of gravity | HIGH (big head = top-heavy, wobbly) | Low (pelvis) |
Standard addition: "toddler proportions — oversized round head, short chubby limbs, round protruding belly, large forehead"
How a Toddler Runs (Different from Adults)
- Wide base — feet far apart, almost waddle-run
- Arms in high guard — elbows bent, hands at shoulder/head height (for balance, NOT pumping like adults)
- Flat-footed — whole foot slaps down, no heel-toe
- Short choppy steps — rapid, legs don't extend far
- Forward lean — whole body tilted, head leading
- Wobbly — slight lateral sway each step
- Toes out — feet point outward
Prompt: "toddler running with wide stance, arms held up at shoulder height for balance, flat-footed slapping steps, body tilted forward, oversized head leading, slight side-to-side wobble"
How a Toddler Climbs Onto a Bed (4 Frames)
- Approach: Standing at bed edge, hands reaching up to grab mattress, chin barely at mattress height, arms fully extended
- Hook: One knee hooked over mattress edge, arms pulling, face scrunched with effort, body pressed against bed side, other leg dangling
- Belly drag: Upper body on mattress, belly flat on edge, one leg still dangling, arms scrambling forward
- Scramble: Both knees on mattress, crawling position, moving away from edge
How a Toddler Reaches
- Whole-hand grab (palmar grasp) — all fingers close against palm, no pinching
- Arm FULLY extended — entire arm stretches straight, shoulder raised
- Whole body leans — torso tilts toward object, not just arm
- Tiptoes — rises to full extension when reaching up
- Tongue out — concentration gesture, tongue often pokes out
Toddler Picking Up Objects
The classic "straight-leg bend" — bends at waist with legs mostly straight, bottom sticking up, head down near ground. NOT a knee-bend squat like adults.
7. Body Mechanics — Common Actions as Freeze-Frames
Climbing Furniture
- "Standing at edge, hands on surface, arms extended, looking up"
- "One knee raised to seat height, hands gripping edge, weight on arms"
- "Upper body draped over edge, belly on surface, one leg dangling"
- "On all fours on surface, just climbed up, settling"
Sitting Down
- "Back to chair, legs touching edge, one hand reaching back to find seat"
- "Knees bending, hips pushing back, torso leaning forward to counterbalance"
- "Seated, weight settling, spine straightening or relaxing into slouch"
Standing Up
- "Upper body tilting forward, head ahead of knees, hands pressing on thighs"
- "Legs pushing upward, body C-to-S transition, hips rising, torso still bent"
- "Fully standing, spine straightening, shoulders settling back"
Turning Around While Walking
- "Head turned over shoulder, body still forward, mid-stride"
- "Body mid-rotation, feet planted, hips turning, shoulders following"
- "Facing new direction, weight settling onto new lead foot"
Adult Hugging Child
"Adult bent at waist or kneeling, arms wrapped around child, child's face pressed against adult's chest, child's short arms reaching partway around adult's neck, adult's hands spanning most of child's back"
Child Being Carried on Hip
"Child seated on adult's jutted-out hip, adult's arm supporting child's bottom, child's legs straddling adult's waist, one small arm around adult's neck, adult's body tilted to counterbalance weight"
Looking Up at Taller Person
"Head tilted far back, chin pointing up, spine arched backward, entire body angled back from feet, mouth slightly open"
8. Foreshortening in Prompts
When a limb points at or away from the camera, it compresses — nearest part appears huge, farthest part tiny.
| Situation | Prompt Language |
|---|
| Arm toward camera | "arm extended toward viewer, hand large in foreground, upper arm compressed behind it" |
| Legs from above | "looking down at legs, thighs foreshortened to ovals, knees prominent, feet small below" |
| Body from below | "extreme low angle, chin and jaw prominent, torso receding upward, head small at top" |
| POV own body | "first-person looking down, chest foreshortened, hands large in foreground, legs tapering away" |
| Child looking up at adult | "low angle looking up, adult's chin dominates, nostrils visible, forehead receding, shoulders wide" |
The Telescoping Effect: When a limb points at the camera, each segment (hand > forearm > upper arm) gets progressively smaller. Joints become the prominent landmarks.
9. Push the Pose (Pixar Principle)
Take any natural pose and exaggerate 20-30% beyond realistic. AI models render at ~70% of what you describe — so prompting at 130% produces 100%.
Test: "If I described this pose to someone who couldn't see it, would they immediately get the emotion?" If not, push further.
Examples:
- Defeat: "spine curved into a deep C, shoulders practically touching knees, head hanging between dangling arms"
- Excitement: "body stretched to maximum height, arms thrown far overhead, mouth wide, eyes huge, toes off ground"
- Shock: "body snapped rigid, arms pressed flat, eyes bulging, leaning backward at impossible angle"
10. Characters of Different Sizes Together
| Technique | When | Prompt |
|---|
| Level matching | Intimate connection | "adult kneeling to be eye-level with child" |
| The tower | Emphasize scale | "child tilted back looking up, adult filling upper frame" |
| The carry | Physical bond | "child on parent's hip, parent tilted to compensate weight" |
| The lean-in | Tenderness | "adult bent at waist, hands on knees, face close to child's" |
| The guide | Protection | "adult behind child, hand on shoulder, child looking forward" |
| Shared focus | Discovery | "both looking at same object, child reaching, parent watching child's reaction" |
11. The Pose Stack (Build Order)
When writing any character into a prompt, layer these:
1. LINE OF ACTION → C/S/straight?
2. WEIGHT → Which foot/surface bears it?
3. LANDMARK TILTS → Shoulder vs hip angles (opposing!)
4. LIMB POSITIONS → Arms and legs specifically (asymmetric!)
5. HANDS & FEET → What are they doing/touching?
6. FORESHORTENING → Any limbs toward/away from camera?
7. PUSH & APPEAL → Exaggerated enough to read instantly?
Quick Fragments
Natural standing: "relaxed contrapposto, weight on [leg], opposite hip dropped, shoulders counter-tilted, one hand [action], head tilted [direction]"
Toddler motion: "toddler proportions (oversized head, chubby limbs, round belly), wide flat-footed stance, arms in high guard, body tilted forward"
Emotional moment: "pushed pose, exaggerated [emotion], clear silhouette, [spine curve], [hand position], asymmetric limbs"
Action freeze-frame: "caught mid-[action], weight [direction], center of gravity [shifted/beyond] support, [leading limb] extended, [trailing limb] following, line of action from [start] to [end]"
Common Mistakes
- Symmetrical poses — both arms same, both legs same. ALWAYS break symmetry.
- No weight specification — character floats. State where weight sits.
- Generic pose language — "standing" or "sitting." Describe the SPECIFIC body configuration.
- Ignoring line of action — pose has no dominant curve. Decide C/S/straight first.
- Adult mechanics on toddlers — adult running form on a 2-year-old. Toddlers run arms-up, flat-footed, wobbly.
- Prompting at 100% — AI renders at 70%. Push to 130% for the pose you actually want.
- Forgetting foreshortening — limbs pointing at camera need explicit description of compression.
- Twinned limbs — both arms doing the same thing. One should always differ.
- No hands/feet description — these are the most expressive parts. Always specify.
- Toddler straight-leg bend ignored — they don't squat like adults. They bend at the waist, bottom up.