@ifc-lite/clash

Clash detection for IFC-Lite. A representation-agnostic core engine plus thin, version-specific source adapters.

• The core (@ifc-lite/clash) operates on ClashElement[] — { key, ref, tag, bounds, positions, indices } — and never imports @ifc-lite/parser/@ifc-lite/query. STEP/IFC4 and IFC5/USD are just adapters that produce those elements.
• Broad phase: BVH (@ifc-lite/spatial). Narrow phase: exact triangle–triangle intersection and exact triangle–triangle minimum distance — no decimation.
• Results classify as hard (interpenetration), clearance (within a gap), or touch (within tolerance, suppressed by default).

import { createClashEngine, CLASH_RULE_PRESETS } from '@ifc-lite/clash';
import { elementsFromStep } from '@ifc-lite/clash/step';

const { elements, exclusions } = elementsFromStep({ store, meshes, modelId: 'm1' });
const engine = createClashEngine({ backend: 'auto' });
const result = await engine.run(elements, [
  { id: 'mep-str', name: 'MEP vs Structure', a: 'IfcPipe*|IfcDuct*', b: 'IfcBeam|IfcColumn|IfcSlab', mode: 'hard' },
], { exclusions });

console.log(result.summary.total, 'clashes');

Includes the TypeScript reference engine, a Rust→WASM kernel kept in lockstep by a differential test (backend: 'auto' picks WASM when available, else TS), STEP and IFC5/USD source adapters, spatial grouping, and a sensible BCF bridge (grouped topics, deterministic GUIDs, optional snapshots). Surfaced through the viewer's clash panel, the ifc-lite clash CLI, the MCP clash_check / clash_matrix tools, and the SDK clash namespace. Design rationale: docs/architecture/clash-detection-plan.md.