threejs-procedural-geometry

Procedural Geometry

Generate geometry from a semantic contract and explicit coordinate frame. Treat polygon operations as the design model and triangle emission as the final compilation step. Do not declare an object complete until its topology, assembly relationships, semantic measurements, and fixed views all pass.

This skill contains exemplary examples and assets beyond descriptive guidance, they're worth studying, referencing, or even copying. Use them sufficiently when relevant and do NOT blindly skip them.

Craft loop

1. Define units, local/world frames, dimensions, bounds, primary profiles, topology intent, shell thickness, apertures, material slots, and triangle band.
2. Declare every required contact, support, clearance, penetration, reveal, moving envelope, and interaction datum.
3. Choose a modeling operation for each visible form: profile extrusion, inset, loft, revolve, sweep, direct-topology aperture, solidify, subdivision, bevel, or fillet.
4. Keep quads and n-gons through design. Preserve one named mesh per semantic part; do not weld unrelated parts or merge material slots yet.
5. Apply modifiers in a deliberate order, then clean inside each part, repair winding, assign a part-specific smooth angle, and emit triangles.
6. Run the polygon topology gate, then audit the named world assembly for coplanar overlap, defects, and substantial solid clashes.
7. Run builder-owned semantic checks, including support, openings, shell thickness samples, ergonomic clearances, and moving extrema.
8. Merge by material slot, audit again, and inspect fixed silhouettes, hidden sides, joints, interaction views, wireframe, normals, and grazing light.

Modeling bar

• Use primitives only for genuinely primitive or hidden structural parts.
• Give every visible manufactured edge a scale-appropriate bevel or fillet.
• Build openings into one closed shell; do not stack a dark plane over a solid.
• Construct thick shells with paired profiles or solidify; never rely on a single surface where an exposed rim reveals thickness.
• Drive mating parts from the same datum. A late visual nudge is a failed dimension contract.
• Choose a continuous mesh for a continuous manufactured form. An arrangement of intersecting primitives is not a substitute for modeling.
• Keep narrow, named allowances only for intersections that are structurally intentional.