ThatOpen Fragment System

Overview

The fragment system is ThatOpen's optimized geometry pipeline for BIM models. It converts IFC files into a GPU-friendly binary format built on FlatBuffers and THREE.InstancedMesh, enabling fast rendering of large models with millions of elements. The @thatopen/fragments package provides the binary format, worker architecture, and core operations. FragmentsManager in @thatopen/components orchestrates model lifecycle, raycasting, data queries, and coordinate alignment.

Pipeline:

IFC File → web-ifc (WASM) → IfcLoader → FragmentsModel (binary .frag)
                                              │
                                    ┌─────────┴─────────┐
                                    │   Fragment[]       │
                                    │  (InstancedMesh)   │