Chapter 2: Proportion Systems

Created by Sarah Choi (prompt writer using ChatGPT)

Proportion Systems (Head Counts, Loomis / Reilly, Stylized Grids)

Proportion is the scaffold that makes gesture believable, anatomy convincing, and costumes wearable. For character concept artists on both the concepting and production sides, proportion systems turn taste into repeatable decisions that survive camera changes and vendor pipelines. This article compares classic systems (head counts, Loomis, Reilly) with stylized grids, then explains how to deploy them for form, perspective, composition, and shippable packages across indie and AAA.

1) Why Proportion Systems Matter

Proportion is not just aesthetics—it’s usability. Head width influences hitbox capsules, leg length drives gait cycles, and hand size affects weapon reads in FPP. A consistent system prevents style drift across skins and keeps outsource vendors on‑model. Your job is to choose or design a proportion rail that matches gameplay and brand, then encode it into every deliverable.

2) Head Counts: Fast Rails for Style & Role

Head counts are the quickest way to telegraph archetype and tone. Use them as a dial, not dogma.

  • 6–6.5 heads (cute/whimsical): Larger heads, short limbs, big hands/feet. Great for approachable, readability‑first casts (MOBA/ISO), where facial reads must survive at small screen sizes.
  • 7–7.5 heads (grounded stylization): Balanced realism for action/adventure. Keeps room for expressive hands while preserving athletic proportions.
  • 8–8.5 heads (heroic realism): Longer legs, narrower heads; used for aspirational or fashion‑forward casts. Caution: watch cape/weapon occlusion in TPP.
  • 9+ heads (mythic/elongated): Elegant, stylized silhouettes for marketing/cinematics or non‑human sophisticates. Ensure gameplay variants down‑rez gracefully.

Production note. Pair head count with absolute height (e.g., 178 cm at 7.5 heads) so modeling can lock scale and texel density.

3) Loomis System: Boxes and Ball for Solid Forms

What it is. Loomis simplifies the skull as a ball plus sliced side planes, and the body as stacked, oriented boxes. It’s powerful for turning gesture into turnable volumes.

Use it for:

  • Establishing cranial tilt and facial plane changes for consistent expressions.
  • Blocking rib cage/pelvis boxes with clear front planes, anchoring perspective before anatomy.
  • Planning costume layer thickness (armor plates, collars) with believable overlaps.

Pipeline value. Loomis planes translate well to orthos and sculpt: the plane breaks become modeling landmarks and material transitions.

4) Reilly Abstraction: Rhythm Lines for Flow & Placement

What it is. Reilly introduces rhythmic lines (brow, cheek, mouth, jaw; deltoid‑pec arc; oblique‑iliac‑thigh sweep) that unify proportion with gesture.

Use it for:

  • Keeping facial features locked to rhythm across expression sheets.
  • Designing muscle rhythm under costume, so folds and seam lines ride real motion paths.
  • Rapidly checking symmetry and tilt without rulers—ideal during explorations.

Pipeline value. Reilly rhythms become stitch paths and panel lines; tech art loves consistent flows around deformation zones.

5) Stylized Grids: Designing Your Own Scale

When IP needs exceed classical rails, create a stylized grid: a page that codifies head, hand, foot, torso, and limb ratios for your cast.

Common stylized families

  • Chibi/SD: 2–3 heads, massive eyes, mitten hands simplified. Gameplay relies on color/pattern and big silhouettes; animation favors squash.
  • Anime hero: 6.5–7.5 heads; long calves, small ankles; big hands for gesture reads; tapered jaw.
  • Western comic heroic: 8–8.5 heads; broad clavicles, long femurs, square hand blocks; strong V‑torso.
  • Mobile ISO readable: 5.5–6.5 heads; big head/hands for icon clarity; simplified ankles and fingers.
  • Creature/alien mix: Non‑human limb ratios and added segments; keep repeatable landmarks (eye line fraction, hand‑to‑thigh relation) so vendors don’t drift.

Pipeline value. Your grid becomes the style bible plate—attach it to every package and skin brief.

6) Proportion → Form, Perspective, Composition

Form. Start with the three masses: head (ball/planes), rib cage (egg/box), pelvis (box). Define their tilt/lean/twist first. Limb lengths then connect masses with believable leverage. Oversized hands/feet can carry expression and ground the pose.

Perspective. Proportion must work at foreshortened angles. Use Loomis boxes and head units to measure receding lengths (e.g., forearm ≈ 1.25 heads toward camera). Prioritize overlap and taper over strict grid perfection for read.

Composition. Proportion choices influence line of action and negative space. Large heads shift focal gravity upward; long legs widen stride and open triangles. Reserve micro‑detail near focal areas (face/hands) and simplify moving extremities.

7) Functional Proportion: Readability & Gameplay

  • Hands: Bigger hands = clearer weapon and spell reads in FPP/TPP. Pair with thicker glove silhouettes for HUD visibility.
  • Feet/Footwear: Slightly larger feet stabilize stance silhouettes and help IK on stairs/slopes.
  • Head/Eyes: Larger heads and eye spacing improve empathy and icon reads; ensure helmet variants respect the same cranial envelope.
  • Shoulder Width: Wider shoulders signal tank; narrow, tapered torsos read as agile/stealth. Maintain readable collars to frame the face.

Tie these dials to role rails (tank/assassin/support) so skins don’t erode class identity.

8) Indie vs AAA: Who Owns the Rails

Indie (1–20 devs). The generalist artist sets the proportion grid once and keeps it alive: silhouettes → orthos → callouts → paintovers. Expect to tune the rail after engine tests (camera FOV, UI scale).

AAA (100+ devs). Exploration/vision sets cast rails and archetype variants; production concept enforces them in orthos/callouts; skins/live‑ops maintain them across seasonal content. Vendor guides include on‑model check panels for each body type.

Across scales, the rule is the same: ship the grid as a deliverable, not just a habit.

9) Deliverables That Lock Proportion

  • Proportion Rail Plate: Head counts beside absolute height; front/side neutral with ruler; hand/foot size swatches; shoulder/hip widths; cranial plane reference.
  • Body Type Matrix: Slim/standard/athletic/heavy/elder/juvenile; keeps cast diversity within rails.
  • Head Variants Sheet: 9 crania with jaw, brow, eye spacing; ties to expression rig.
  • Foreshortening Ladder: Arm and leg depth steps to guide animation/illustration.
  • Costume Fit Overlays: Base body with gear volumes; skirt/cape profiles that respect rail and camera.

Package these with naming (CH_Cast_Rail_v###) and a change log.

10) Collaboration Map

Design (Game/System/Level): Align role dials (shoulder width, hand size); confirm hitbox capsules; validate ladder/climb fits.

Animation/Tech Anim: Validate joint ranges; request skirt profiles and belt placements; confirm hand/foot proportions for IK.

Character/Tech Art: Lock texel density vs height; agree on LOD preservation along rail edges (chin, collar, emblem size).

VFX/Audio: Ensure emitter/socket sizes scale with hand/weapon proportions; avoid FX occluding small heads.

UI/UX: Confirm portrait and icon crops; test head/hand scale in HUD and inventory.

Cinematics/Marketing: Approve face proportions and jaw planes for close‑ups; supply beauty poses that respect rails.

Production/Outsourcing/QA: Enforce on‑model checks; track deviations; approve regional variants that maintain rail silhouette.

11) Failure Modes & Fixes

  • Floaty legs (torso too long). Rebalance pelvis drop and femur length; widen stance triangles.
  • Baby‑hand syndrome. Scale hands up 5–10%; thicken glove edges; ensure weapon handles scale accordingly.
  • Helmet drift. Lock cranial planes early; ship a helmet envelope diagram.
  • Style soup across skins. Keep rail overlays in every skin brief; forbid silhouette changes outside class guardrails.
  • Foreshortening collapse. Add overlap markers and taper rules to the foreshortening ladder; run a 1‑second read test.

12) Drills (Daily/Weekly)

Daily (20–30 min):

  • Draw a rail plate from memory (front/side), then correct with reference.
  • Do a hand/foot scale sweep (–10% to +20%) and pick the best read for your camera.

Weekly (60–90 min):

  • Build a body type matrix for one archetype; test in engine thumbnails (5 m/10 m/20 m).
  • Create a foreshortening ladder for the forearm and lower leg with weapon/boot overlays.

13) Review Gates

  • Gate A — Rail Approval: Head count + absolute height + body type matrix signed.
  • Gate B — Turnable Volumes: Loomis planes and Reilly rhythms validated in neutral and 3/4.
  • Gate C — Camera Read: ISO/TPP/FPP thumbnails pass 1‑second read; adjust hand/head dials as needed.
  • Gate D — Package: Orthos with scale bars, callouts with rail overlays, vendor on‑model check panel included.

14) Final Thought

Proportion systems are creative constraints that accelerate you. Choose the rail that serves gameplay and brand, articulate it with Loomis solidity and Reilly rhythm, and encode it in plates that every collaborator can trust. Do this, and your characters will stay on‑model across cameras, cultures, and seasons—without sacrificing personality.