Chapter 1: Material ID Boards

Created by Sarah Choi (prompt writer using ChatGPT)

Material ID Boards (Skin, Scale, Feather, Horn) for Creature Concept Artists

1. Why Material ID Boards Matter for Creatures

When you design a creature, you’re not just drawing anatomy—you’re specifying how light should behave on every patch of its body. Is the belly thin and glowing in backlight? Do the scales catch sharp, glittery highlights? Does the horn feel dry and chalky or polished and oily? Material ID boards are the bridge between your visual idea and a production‑ready PBR (physically based rendering) surface plan.

A Material ID board is a focused sheet that maps out the major material families on a creature—skin, scales, feathers, horn/keratin—and shows how they behave across:

  • SSS (subsurface scattering): how light penetrates and diffuses through the material.
  • Anisotropy: how highlights stretch or directionalize along fibers, grooves, or barbs.
  • Wet/dry mixes: how the same material reads in different hydration states (sweat, slime, rain, drying mud, etc.).

For concept‑side artists, Material ID boards keep your designs consistent across paintings, pose explorations, and key art. For production‑side artists, they become a practical spec sheet for texturing, shading, and VFX: a shared language between concept, lookdev, tech art, and lighting.

2. What is a Material ID Board in PBR Terms?

In game and film pipelines, “Material IDs” often refer to color‑coded masks in a texture file. As a concept artist, you’re pushing that one step earlier: you’re building a visual matrix of material zones and linking each color code to clear behavior notes:

  • A simple creature orthographic (side/front/back) with zones marked in flat ID colors.
  • A swatch grid where each ID color corresponds to:
    • A base PBR read: albedo, roughness, specularity, SSS amount.
    • A few lighting thumbnails (rim‑lit, top‑lit, backlit) to show how it behaves.
    • Notes on anisotropy direction (arrows), wet/dry variants, and damage/weathering if relevant.

Even if you’re not writing shader graphs, you’re defining how they should feel. The board gives downstream artists:

  • Consistent naming (e.g., SKIN_SOFT_THIN, SCALE_DORSAL_ARMORED, HORN_POLISHED).
  • A quick reference for how far they can push glossiness, color, or translucency without breaking your intent.

3. Quick PBR Refresher for Creature Surfaces

You don’t need to be a TD, but you should understand a few PBR levers in creature context:

  • Albedo/Base Color: The “ink” of the surface without lighting. For organic creatures, this is usually medium‑range (not pure black or white).
  • Roughness: Controls how broad or sharp highlights appear. Rough = diffuse, chalky. Smooth = glossy, mirror‑like.
  • Metalness: Almost always non‑metal (0) for skin, feathers, scales, horn. “Metallic” creatures are a deliberate stylization.
  • Normals / Micro‑normals: Small surface bumps that break up reflections; essential for scales, feather barbules, keratin striations.
  • SSS / Transmission / Thickness: Controls how much light penetrates and glows through subsurface tissue like skin, fins, or translucent scales.
  • Specular / IOR (Index of Refraction): Subtle control over how intense and “tight” the highlight is.
  • Anisotropy: Governs how highlights stretch along a preferred direction (fur flow, feather alignment, horn grooves).

Your Material ID board doesn’t show these channels separately, but your callouts describe them visually. Example note:

VENTRAL_SKIN_THIN – high SSS, low roughness in wet state, pink subsurface, visible veins in backlight, slight anisotropy along stretch lines.

This kind of callout tells a texture artist exactly what to target in their shader.

4. Core Material Families: Skin, Scale, Feather, Horn

We’ll walk through each major family with:

  • Real‑world anchor
  • Visual cues
  • SSS, anisotropy, wet/dry logic
  • Concept vs production usage

4.1 Skin & Soft Tissue

Real‑world anchors: human skin, amphibians, elephants, whales, hairless cats, bat wings, axolotls.

Visual cues:

  • Soft transitions between light and shadow.
  • Color variation tied to blood flow (ears, nose, thin areas are redder or pinker).
  • Wrinkles, folds, and stretch lines that catch specular in different ways.

SSS for skin:

  • Thin areas (ears, nose, eye ridges, webbing, fins) have strong SSS. In backlight they glow, often a saturated red/orange.
  • Thick areas (calloused hands, armored shoulders, pads) have weaker and deeper SSS—light doesn’t glow as much, but edges still feel soft.
  • On your board, show two swatches for skin: THIN_SSS and THICK_SSS with mini backlit thumbnails.

Anisotropy for skin:

  • Usually low, but you might suggest subtle directionality where skin stretches: the highlight can smear along wrinkles or tension lines.
  • For stylized creatures with very taut skin (e.g., reptiles, hairless beasts), you can exaggerate this in your board: arrows indicating stretch direction.

Wet/dry mixes:

  • Dry skin: higher roughness, broader highlights, visible pores, chalky elbows/knees.
  • Sweaty/damp skin: reduced roughness in specific zones (forehead, spine, underarms), sharper highlights, darker local color.
  • Slimy or mucus‑coated skin (amphibians, underwater creatures): extremely low roughness, sometimes dual‑lobe specular (broad base + tight wet lobe), strong SSS.

On your board, create skin swatches such as:

  • SKIN_DRY_BASE
  • SKIN_SHEEN_SWEAT
  • SKIN_SLIME_OVERLAY (for amphibian or deep‑sea creatures)

Provide small lighting studies: a sphere or cropped torso patch where one half is dry, the other half is wet—same albedo, different spec/roughness.

Concept vs production usage:

  • Concept side: Use your skin ID swatches to keep consistent rim‑light and backlight behavior when painting different scenes. Don’t randomly change how translucent the ears are from illustration to illustration.
  • Production side: Your SSS notes guide thickness maps, transmission color, and blend masks (e.g., thin skin mask around eyes and webbing). Wet/dry notes suggest separate shader states or dynamic VFX (sweat during combat, slime when emerging from water).

4.2 Scales & Scutes

Real‑world anchors: snakes, crocodiles, pangolins, fish, certain birds’ legs, dragons (fictional but inspired by reptiles and fish).

Visual cues:

  • Clear tiling or overlapping pattern.
  • Sharp transitions between light and dark as facets catch light.
  • Often a layered feeling: a thinner varnish on top of a denser base.

SSS for scales:

  • Many scales are relatively opaque, with subtle subsurface only along edges or thin tips.
  • Fish scales and some fantasy dragon scales can have a semi‑translucent rim; backlight may create a slight fringe.
  • Use board swatches like SCALE_DORSAL_OPAQUE vs SCALE_VENTRAL_SEMI_TRANS and show them in backlight thumbnails.

Anisotropy for scales:

  • Micro‑grooves along each scale can create weak anisotropy: highlights can stretch along the long axis of the scale or along growth striations.
  • On your board, draw arrows across a sample scale patch showing the groove direction. A note might read: “Subtle anisotropic spec along scale length; stronger at polished edges.”

Wet/dry mixes:

  • Dry scales: moderate to high roughness, especially on worn surfaces, with micro‑chipping and dust.
  • Wet scales: significantly sharper highlights, darkened value, reflections become more mirrorlike.
  • For amphibious creatures, show a gradient transition where scales near waterline are wetter, with streaks of drying water or slime.

Swatches to include:

  • SCALE_ARMOR_DRY – high roughness, matte, chipped edges, dust in crevices.
  • SCALE_ARMOR_RAIN – water beads, tiny spec hits, darker overall.
  • SCALE_SHIMMER_IRIDESCENT – if applicable, call out thin‑film spec for fantasy or fishlike scales.

Concept vs production usage:

  • Concept side: Your scale board guides pattern scale and value grouping. It prevents you from painting scales as noisy texture without respecting the overall light falloff and spec lobe.
  • Production side: The board informs separate material layers: base albedo/roughness normals for scale plates, plus optional clear‑coat or wetness layers; anisotropy settings for the fine grooves; and masks for wet edge darkening.

4.3 Feathers

Real‑world anchors: birds of prey, waterfowl, owls, corvids, penguins, fantasy winged creatures.

Visual cues:

  • Organized directional flow following wing and body aerodynamics.
  • Soft edge breakup at the silhouette.
  • Specular highlights that elongate along feather barbs (classic anisotropy).

SSS for feathers:

  • Feathers are mostly opaque at macro level, but at thin edges and downy sections they transmit a soft halo of light.
  • Flight feathers in backlight may show internal structure—shafts and barbs as darker silhouettes against glowing vanes.
  • In your board, show a feather swatch with a backlit thumbnail: glowing outer edges, internal veins.

Anisotropy for feathers:

  • This is the big one. Feathers exhibit noticeable anisotropic sheen along barbs.
  • On your board, for each feather type (primary flight feather, contour feather, down), draw arrows in the direction of the specular stretch.
  • Swatches might include:
    • FEATHER_PRIMARY_SATIN – strong anisotropy, mid roughness, tight directional sheen.
    • FEATHER_DOWN_MATTE – low anisotropy, high roughness, almost velvet.

Wet/dry mixes:

  • Dry feathers: fluffy, layered, micro‑shadows between layers, richer color.
  • Wet feathers: clumped, darker value, reduced volume, specular concentrated on water film instead of individual barbs.
  • For aquatic or storm‑exposed creatures, show a sequence: dry → damp → soaked → partially dried, with annotations on how roughness and silhouette change.

Concept vs production usage:

  • Concept side: Use your feather ID board to stay consistent about how wings read in rim light, how saturated they appear in sunlight, and how they collapse when soaked or burned.
  • Production side: The anisotropy notes inform shader direction vectors or tangent maps; wet/dry variations encourage layered materials or blend shapes for groom clumping.

4.4 Horn, Claw, Beak & Keratin Structures

Real‑world anchors: antlers, rhino horns, goat horns, talons, beaks, hooves.

Visual cues:

  • Layered, fibrous internal structure (particularly horns and hooves).
  • Surface striations running along growth direction.
  • Varying glossiness: matte at worn tips, glossy at polished or oiled areas.

SSS for horn & keratin:

  • The core may be quite dense, but edges and tips can exhibit subtle translucency when backlit, especially in lighter colors.
  • Think of a deer antler rim glowing faintly, or a thin beak edge catching warm light.
  • Swatches: HORN_THICK_OPAQUE vs HORN_EDGE_SSS with a backlit example.

Anisotropy for horn & keratin:

  • Growth rings and grooves create strong directional striations.
  • Highlights stretch along the length of the horn or claw, not across it.
  • On your board, show a horn cylinder with the spec highlight smeared longitudinally, plus arrows and a note like: “High anisotropy along growth axis; gloss highest at polished ridges.”

Wet/dry mixes:

  • Dry horn: chalky, micro‑pitted, high roughness, visible wear marks.
  • Polished or oiled horn: lower roughness, deeper color, richer spec.
  • Wet horn (rain, blood, slime): extra specular lobe from thin liquid film, especially at tips and edges.

Swatches:

  • HORN_DRY_OLD
  • HORN_POLISHED_ELITE (for ceremonial or high‑status creature variants)
  • HORN_WET_BATTLE (blood, rain, or saliva glaze)

Concept vs production usage:

  • Concept side: Map where horns and claws sit on the status spectrum: worn and chipped for veterans, polished for ceremonial mounts. Your material ID board becomes a storytelling tool.
  • Production side: Your board drives multiple keratin materials with different roughness/normal intensity and optional wet overlays. It also encourages separate masks for tips/edges versus the base.

5. SSS Logic: Where Creatures Glow

SSS is often overused as “everything glows red.” A good Material ID board targets areas where SSS matters most and distinguishes between materials.

For each creature, annotate on your orthos:

  • Primary SSS zones: ears, nostrils, lips, eye bags, webbing, thin fins, membranes.
  • Secondary SSS zones: softer belly, inner thighs, fingers/toes, thin tail sections.
  • Minimal SSS zones: thick scales, hoof cores, heavy horn bases, dense callouses.

Then, for each of the four material families, clarify SSS behavior:

  • Skin: from strong (thin) to weak (thick), tied to blood color and thickness.
  • Scales: mostly surface reflection, with only rim or thin edges glowing.
  • Feathers: soft, subtle halo at edges/down.
  • Horn/keratin: mild edge glow on thin, light‑colored sections.

On the board, use small backlit silhouette thumbnails to show SSS patterns: a head in profile glowing at ears and nostrils, a wing membrane glowing between bones, a horn tip glowing slightly while the base stays opaque.

This helps both painters and shader artists avoid “neon gummy bear” syndrome and keeps SSS purposeful and believable.

6. Anisotropy Logic: Flow Over Forms

Anisotropy is all about directional specular—highlights that stretch along an axis. In creatures, it visually reinforces:

  • Feather direction
  • Scale growth patterns
  • Horn/claw growth
  • Even subtle stretch lines in skin

On your Material ID board:

  • Overlay flow arrows on your creature orthos for each material family.
  • Show a micro‑patch swatch (a 2D tile) for feathers, scales, horn—each with the highlight drawn elongated in the proper direction.
  • Add notes such as:
    • “Feather spec stretches along barbs; breaks at wing joints.”
    • “Scale highlights aligned with dorsal ridge; reduced anisotropy on belly scales.”
    • “Horn spec follows curve axis; chipped sections have localized rough, non‑anisotropic spots.”

For concept artists, this gives you a mental map of how to brush highlights along a form instead of just stamping white streaks. For production artists, it suggests tangible shader parameters and tangent directions.

7. Wet/Dry Mixes: State Changes, Not New Materials

One of the most powerful uses of Material ID boards is to show state changes without inventing entirely new materials.

Instead of treating “wet” as a separate material, think of it as a layer over the existing one:

  • Local darkening (less diffuse reflection, more specular).
  • Boosted specular intensity and lowered roughness in wet zones.
  • Directional streaks where water flows due to gravity or motion.

For each family:

  • Skin: sweat patterns, slime patches, rain running down; pooling in creases; drying edges.
  • Scales: water beading on ridges, collecting in gaps; slime film on belly; drying spots on dorsal ridges.
  • Feathers: clumping and darkening; volume collapse; reflective wet patches on outer feathers.
  • Horn/keratin: sharp, cold spec on tips; fluid stains; mud crust at bases.

Your board should include pairs or triplets:

  • BASE_DRY vs RAIN_SOAKED sphere or plane.
  • Annotated with arrows indicating water flow and notes like “Wetness localized to ventral skin, inside mouth, horn tips after feeding.”

Concept artists can then depict consistent wetness behavior in narrative scenes, while production teams can design:

  • A global wetness slider that ramps roughness/spec masks.
  • Per‑zone wetness masks (e.g., ventral only, muzzle only).

8. Building a Creature Material ID Board: Step‑by‑Step

Here’s a workflow you can reuse across projects.

Step 1: Inventory Your Material Families

Start with a neutral orthographic or line drawing of your creature.

  • Circle or color‑block where skin, scales, feathers, horn/keratin appear.
  • Note special cases: scar tissue, callouses, bio‑luminescent patches, diseased or diseased surfaces if relevant.

Write a text list:

  • SKIN_THIN, SKIN_THICK, SKIN_SCAR
  • SCALE_DORSAL, SCALE_VENTRAL, SCALE_FACE
  • FEATHER_PRIMARY, FEATHER_DOWN, FEATHER_DECORATIVE
  • HORN_BASE, HORN_TIP, CLAW, BEAK

These become your Material ID names.

Step 2: Assign ID Colors & Zone Map

On a copy of your orthos:

  • Fill each material zone with a distinct flat color.
  • Keep it clean and bold—you’re not painting beauty, just IDs.
  • Label each zone in small text, matching your list.

This is your high‑level Material ID map.

Step 3: Swatches for Each Material ID

Create a swatch grid. For each material ID:

  • Paint a small shaded sphere or cube representing its default (dry, neutral) look.
  • Next to it, paint a micro close‑up: a 1–2 cm patch that shows the texture and scale.
  • Add a small backlight or rim‑light thumbnail if SSS is important.
  • For anisotropic materials, draw arrows showing highlight direction.

Add notes:

  • Roughness range (e.g., 0.2–0.5 light‑to‑dark arrow).
  • SSS strength (e.g., “thin SSS: strong red rim”, “horn edge: mild warm fringe”).
  • Wet variants (e.g., “wet state: roughness ↓, spec ↑, darkened albedo by ~10%”).

Step 4: Wet/Dry & State Variants

For key materials, add state variations:

  • SKIN_THIN_DRY vs SKIN_THIN_SWEAT.
  • FEATHER_PRIMARY_DRY vs FEATHER_PRIMARY_SOAKED.
  • SCALE_DORSAL_DRY vs SCALE_DORSAL_SLIME.
  • HORN_TIP_DRY vs HORN_TIP_BLOODIED.

Show them side‑by‑side under the same lighting. This makes it obvious that state change is mostly about roughness/spec/SSS, not a brand‑new color.

Step 5: Production Notes & Naming Conventions

Dedicate a small section of the board to production‑minded notes:

  • Suggested shader slots: “Use existing skin shader with modified thickness map,” “Scales re‑use reptile master shader; add clear coat layer.”
  • Grouping: which IDs can share the same shader, which ones need unique ones.
  • LOD guidance: which material details can be simplified or dropped at distance (e.g., horn striations, feather micro‑sheen, fine scale normals).

This makes your board immediately actionable for a 3D artist opening Substance, Mari, or a studio’s in‑house tool.

9. Using Material ID Boards in the Concept Phase

Once the board exists, treat it as a contract with yourself:

  • When painting key art, keep the board on a second monitor. Ask: “Does this wing highlight match my feather anisotropy swatch?”
  • When sketching new poses, base your rim‑light and SSS decisions on the existing SSS thumbnails.
  • When designing variants (e.g., desert vs arctic morphs), reuse material IDs but adjust only what matters: dryness, frost sheen, dust masks.

The more consistent your material behavior is across images, the more trustworthy your creature feels—especially in a studio context where many people will touch the asset.

10. Using Material ID Boards on the Production Side

For production‑side creature concept artists (or hybrid 2D/3D artists), Material ID boards are your handoff spine:

  • They plug directly into Material ID maps for baking and texturing.
  • They help you decide when to split UDIMs or material slots (e.g., separate slot for wet inner mouth vs dry outer skin).
  • They speed up reviews: art directors and tech art can comment on one sheet instead of chasing inconsistencies across multiple images.

A typical pipeline might look like:

  1. Draw Material ID board.
  2. Collaborate with tech art to map IDs to existing shader libraries.
  3. Use the board as a target while painting textures or doing lookdev renders.
  4. Update the board if a better shader solution appears, so 2D and 3D remain synced.

11. Common Pitfalls & How to Avoid Them

Pitfall 1: Everything is one generic “skin.”
Solution: Force yourself to distinguish at least three skin types (thin, thick, scarred/calloused) and give each its own SSS/roughness logic.

Pitfall 2: Irrelevant SSS.
Solution: Don’t make scales glow like gummy candy unless it’s a magical design choice. Limit strong SSS to thin, vascular tissues.

Pitfall 3: Ignoring anisotropy.
Solution: For feathers, scales, and horn, always define a flow direction. If highlights are painted randomly, creatures feel like plastic toys.

Pitfall 4: Wet equals “just add white highlights.”
Solution: Remember that wetness darkens diffuse reflection. Reduce roughness, deepen value, and sharpen reflections; don’t just add white.

Pitfall 5: Material ID boards that are too abstract.
Solution: Include at least one real‑world photo reference row (or clearly linked ref callouts) to ground your swatches.

12. Leveling Up: Material ID Boards as a Creature Design Superpower

The more creatures you design, the more you’ll see patterns in how materials behave across species and biomes. Over time you can build a library of reusable Material ID families:

  • A universal “amphibian wet skin” set.
  • A “raptor feather package.”
  • A “herbivore horn and hoof” bundle.

As both a concept and production‑side creature artist, your job is to translate biology into controllable light behavior. Material ID boards help you:

  • Make better design decisions (what is skin vs scale vs horn and why?).
  • Communicate clearly with texturing and lookdev teams.
  • Keep your creatures consistent across poses, scenes, and even entire projects.

Once you start building Material ID boards for skin, scales, feathers, and horn, you’ll find they become as indispensable as your anatomy studies. They’re not just technical charts—they’re story tools, telling your lighting team and your players what this creature feels like before anyone even touches the model.