3D art guidelines

Molen's baseline is a readable polygonal world: strong silhouettes, restrained palettes, clear material blocks, and modest surface detail. A building or prop should remain recognizable when textures are disabled. Textures add material character such as brick courses; they do not carry the entire identity.

These guidelines apply to imported static GLBs, built-in instanced props, and parameterized worldgen buildings. They are authoring targets, not new runtime hard limits. Use the existing model asset workflow for import, validation, hashes, hosting, and captures.

Recognition and shape

Work from large to small: footprint and height, roof and massing, entrance and facade rhythm, then sign and surface detail. For a mapped business, use a generic category wordmark, an initial-based emblem, a controlled accent color, and an entrance treatment. Source-inspired palettes may distinguish descriptor variants, but model IDs, filenames, displayed names and emblem geometry stay generic.

Keep mapped footprints, courtyards, height, and minimum height when supplied. Missing height is unknown: the category recipe supplies a conservative default. An identified tenant does not own an entire strip mall. Apply its facade locally and retain other tenants.

Flat or gently faceted surfaces are the default. Use hard normals on architecture and metal edges; smooth normals only on deliberately round shapes. Curved identity marks should still read at low polygon counts. Avoid tiny bevels, microdisplacement, alpha-card foliage and surface noise that shimmer at street-view distance. Signs face +Z in their own frame and must read from the street; never mirror text to compensate for an incorrectly oriented facade.

Scale and pivots

Use meters, +Y up, and transforms near unit scale. Ground-standing props have their base at Y=0. Wall-mounted signs have a documented attachment plane. Record front direction and native dimensions alongside each model.

Reference	Baseline
Adult scale reference	1.75 m
Child figure	1.1–1.4 m
Dog at the shoulder	0.5–0.7 m
Horse at the withers	1.5–1.7 m
Ordinary door	0.9–1.1 m wide, 2.1–2.4 m high
Commercial double entrance	1.6–2.2 m wide, up to 2.6 m high
Bench	About 1.8 m wide; seat about 0.48 m high
Bicycle hoop	About 0.85 m high
Street lamp	About 7 m; use a mapped height when present
Charging pedestal	About 1.8 m
Canonical facade sign	4 × 1.35 m; base Y=0, front +Z

Check scale beside a person, a door, and a road. Make signs readable through proportions and contrast before increasing their size. Do not stretch a mark independently in X and Y. Mapped tree height and crown diameter scale normalized tree models independently in height and horizontal diameter; missing species remains an estimate.

Fidelity and geometry budgets

Use the lowest detail that survives the intended view. These targets describe one reusable model; scene and tile budgets still control total instances and building vertices.

Asset	Near target	Medium/distant treatment
Identity sign	Under 650 triangles, one material	Remove small lettering first; retain symbol and color
Bench, rack, charger, lamp	50–500 triangles	Merge slats/cables; retain silhouette
Ordinary tree	300–2,000 triangles	Fewer crown clusters, then a faceted crown/cone
Small static building	1,000–8,000 triangles	Remove furniture and small facade details
Procedural building	Budgeted per outline	Keep measured envelope, main roof and identity where feasible
Figure (human or animal)	1,000–4,000 triangles, one vertex-color material	600–900 medium tier; 100–300 rigid distant tier

Higher budgets need a visible reason and a distance fallback. Repeated street furniture and signs should be instanced by model reference. Prefer a shared vertex-color material; do not allocate one material or texture per store. Never put an unlimited number of signs on a complex outline: the current frontage contract admits at most twelve per generated building.

The sign library preserves exact geometry between instances. Source business identity controls matching; stable feature identity controls placement and variation. Do not use wall-clock time, unseeded randomness, or locale-dependent sorting to generate geometry.

Figures

Figures (guide) stay left of the uncanny valley on purpose: a head about one sixth of the height for adults and closer to a quarter for children, mitten hands, block shoes or hooves, disc eyes and brows with no mouth, nose or teeth, hair as a solid shell, and clothing as vertex-color blocks with hard edges at cuffs, hems and collars. Segments are smooth within themselves and low in ring count (eight to twelve sides), joints share rings with two bone influences, and each figure uses three to five intentional colors from its palette. Animals follow the same rules: a barrel body, cone ears, a snout, hooves or paws, and one marking color. Review every preset from the front, three-quarter, rear and gameplay distance (molen figure preview --angles review) beside a door and a bench before accepting a look.

Color, light and material response

Use muted wall/ground colors and reserve saturated accents for identity and wayfinding. Limit each object to roughly three to five intentional colors, excluding small surface variation. Roof and foundation values should separate from the wall without outlining every edge.

Author with neutral daylight, real cast shadows and a shadow-receiving ground. Base color must not contain baked directional shadows or highlights. Prefer rough matte paint, brick, concrete, wood, and coated metal; glass should read as glazing without becoming a mirror everywhere. Use material variation to explain construction, not to disguise missing geometry.

For GLB PBR assets, base color/emissive are sRGB; normal, roughness, metalness and occlusion are linear data. Existing worldgen palette helpers and three.js color inputs have different conversion paths: compare rendered swatches when transferring colors between static and procedural assets, rather than copying a linear buffer value into an sRGB authoring field.

Canonical material library

Reuse the default pack's stable material IDs before adding another texture. The library already contains brick, stucco, concrete, siding, stone, roofing and glazing; the material catalog records intended uses and physical repeat sizes.

Use 256² or 512² seamless procedural maps for common repeated surfaces. Larger textures belong to a visibly close hero asset and must fit its memory budget. Start at 64–128 texels per meter at the closest ordinary view and check mipmapped distance views. Specify physical UV repeat size: a two-meter facade should not accidentally contain two-meter bricks.

Patterns should have subdued contrast. Prefer a small shared base-color/roughness set over unique store textures. Normal maps should describe mortar or subtle grain, not change the silhouette. Pack bitmap GLB textures to KTX2 with mipmaps for shipping, per the asset workflow. Runtime matgraph textures remain small and shared; they do not pass through asset packing.

Persisting reusable models

Store individual sign and furniture definitions in the default pack's landmark manifests, with stable IDs, versioned parameters and shared generators. Keep source-ID/name matching in the Earth business catalog. Reuse architectural styles and material graphs instead of copying their rules into each mapped-business descriptor. A new store palette or an existing sign-symbol variation should be a data edit.

Static and procedural parity

A static asset and its procedural counterpart must agree on scale, pivot, front direction, palette, and intended detail tier. The identity and furniture generators are exported through the worldgen kernel. Their buffers can be exported with encodeGlb; import the resulting GLB through the normal asset workflow when a project needs a standalone static asset.

Procedural building bakes currently include the building mesh; attached sign/furniture instances remain separate placements. To preserve a mapped-business treatment in a static scene, retain those placements or explicitly assemble and import the complete model. Do not silently ship the bare shell as an equivalent bake.

Review before adding to the library

Capture front, three-quarter, rear, and a normal gameplay-distance view. Include a neutral ground, a scale reference, and a texture-disabled view. Verify outward normals, legible unmirrored signs, ground contact, and believable shadows. Test at least two scales and a rotated placement. For storefronts, include one shared building and a footprint with a courtyard or seam.

Compare near and distant representations for popping, silhouette drift and floating pivots. Record triangles, material groups, model reference, texture sizes, source hashes for imported assets, and the generator/catalog version. Keep a repeatable scene or batch fixture and a reviewed visual regression. A successful build without inspected images is not visual approval.

The recognizable places guide explains how to extend the first identity library and use the art-review showcase.