Raycast the triangle field.

A source-backed interactive geometry contract: one non-indexed BufferGeometry owns positions, flat normals, and vertex colors; a Raycaster selects a face and a line loop reveals its three edges.

This route claims the installed BufferGeometry + Raycaster interaction contract only. The official 5,000-triangle random field, Stats presentation, exact pointer/camera composition, device/compiler/backend coverage, and whole-example fidelity remain separate.

Sources: official interactive BufferGeometry example · BufferGeometry · Raycaster