kernelcad-patterns

kernelCAD — mechanical patterns

Shape.patternLinear / .patternCircular / .patternGrid produce a single FeatureRecord per call — one editable unit, one row in inspect({ of: 'features' }), one undo step. The pattern composes the source feature into N instances; instance 0 is the source position.

// Linear: 5 fins evenly spaced 10 mm along +X
const fin = box(2, 20, 8);
const heatsink = plate.add(fin).patternLinear({ count: 5, direction: [1, 0, 0], spacing: 10 });

// Circular: 6 spokes around the +Z axis
const spoke = rib.patternCircular({ count: 6, axis: [0, 0, 1] });

// Grid: 4x3 bolt-hole array on a plate
const mountBolt = plate.hole('top', { u: 0, v: 0, diameter: 5, depth: 'through', name: 'mountBolt' });
const drilled = mountBolt.patternGrid({
  x: { count: 4, direction: [1, 0, 0], spacing: 25 },
  y: { count: 3, direction: [0, 1, 0], spacing: 25 },
});

API

.patternLinear({ count, direction, spacing }: {
  count: number;                       // integer >= 2
  direction: [number, number, number]; // unit-ish; will be normalized
  spacing: number;                     // non-zero finite mm
}): Shape

.patternCircular({ count, axis, angleDeg? }: {
  count: number;                       // integer >= 2
  axis: [number, number, number];      // rotation axis
  angleDeg?: number;                   // total angle; defaults to 360
}): Shape

.patternGrid({ x, y }: {
  x: { count: number; direction: [number, number, number]; spacing: number };
  y: { count: number; direction: [number, number, number]; spacing: number };
}): Shape

Geometric semantics

Pattern is implemented as cumulative boolean union of transformed source copies. Additive features (boxes, ribs, fins, tabs, spokes) pattern cleanly. Patterning a subtractive feature (hole, cutout) only preserves the per-instance void when adjacent bodies are disjoint — overlapping patterned bodies cause the inner void to be filled by the outer body's solid (boolean-union semantics).