Threejs Procedural Fields

Procedural Fields

Do not start by stacking noise. Start by defining the fields the object physically or stylistically needs.

Field contract

Before shader code, write a field bundle:

coordinates
  → macro form
  → meso structure
  → derived causes
  → material channels

Example:

sphereDirection
  → warpedDirection
  → elevation + ridges + craterDepth
  → slope + cavity + latitude + moisture
  → biome + color + roughness + bump

Required workflow

• Choose coordinates that remain stable under camera and object motion.
• Lock real or perceptual scale for each frequency band.
• Create named primary fields. Never hide the whole look in one expression.
• Derive secondary fields from causes: slope from normals, shore from sea-level distance, wear from exposure, dirt from cavity.
• Reuse the same fields across color, roughness, normal, displacement, emission, and scattering.
• Add debug output for every named field.
• Filter high-frequency fields by derivatives, tessellation density, or camera distance.

Read references/field-stack-recipes.md

before implementation. It records sphere, terrain, water, and

structured-placement field contracts plus common parity defects.

Read the

procedural planet surface

for a shared CPU/GLSL field bundle whose height, continents, climate, biomes,

roughness, and normals remain independently inspectable.

Non-negotiable rules

• Independent noise per channel produces visual soup. Share structure.
• Domain warp the coordinates, not every result.
• Warp spherical coordinates tangentially, then renormalize.
• Use different frequency bands for silhouette, regions, surface breakup, and micro-normal.
• Do not displace geometry with frequencies the mesh cannot represent.
• Keep categorical masks broad enough to avoid isolated “bubble” regions.
• Parameter names must describe perception: ridgeWidth, coastBlend, cavityDarkening, not noise3Amount.

Routing boundary

Use this skill when the shared field model is the task. Use

$threejs-procedural-materials when the task is channel assembly and material

response, and $threejs-procedural-planets when the deliverable is a complete

planetary body.