2nd/10_Wiki/Topics/DevOps_and_Security/IFCjs (Fragment).md

id, title, category, status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, verification_status, tags, raw_sources, last_reinforced, github_commit, tech_stack

id	title	category	status	canonical_id	aliases	duplicate_of	source_trust_level	confidence_score	verification_status	tags	raw_sources	last_reinforced	github_commit	tech_stack
wiki-2026-0508-ifcjs-fragment	IFCjs (Fragment)	10_Wiki/Topics	verified	self	IFC.js ThatOpen Fragment web-ifc BIM web viewer	none	A	0.85	applied	bim ifc threejs web fragment		2026-05-10	pending	language framework TypeScript Three.js, web-ifc, ThatOpen Components

IFCjs (Fragment)

매 한 줄

"매 IFC BIM model 의 web-native streaming 형식". 매 2021 IFC.js (Antonio Gonzalez Viegas) → 매 2024 ThatOpen Components 로 rebrand 된 toolchain. 매 Fragment format 매 IFC 의 매 GPU-friendly binary representation — 매 1GB IFC 가 매 50MB Fragment 로 압축, 매 browser 의 매 instant load.

매 핵심

매 IFC 의 limitation

• 매 STEP-based ASCII format — 매 100MB+ project 매 routine.
• 매 spatial hierarchy + property + geometry 매 모두 nested — 매 partial load 의 X.
• 매 Three.js 의 직접 render 의 X — 매 tessellation needed.

매 Fragment 의 solution

• 매 web-ifc (WASM) 가 매 IFC parse + tessellate.
• 매 결과를 매 Fragment binary (FlatBuffers-based) 로 serialize.
• 매 InstancedMesh 단위 grouping → 매 draw call 격감.
• 매 property data 매 별도 SQLite-WASM file → 매 lazy query.

매 응용

1. 건축 설계 review web tool.
2. Construction 현장 mobile BIM viewer.
3. Facility management dashboard.
4. Clash detection web service.

💻 패턴

1. ThatOpen Components 초기화 (2026)

import * as OBC from "@thatopen/components";
import * as OBCF from "@thatopen/components-front";

const components = new OBC.Components();
const worlds = components.get(OBC.Worlds);
const world = worlds.create<
  OBC.SimpleScene, OBC.SimpleCamera, OBCF.PostproductionRenderer
>();

world.scene = new OBC.SimpleScene(components);
world.renderer = new OBCF.PostproductionRenderer(components, container);
world.camera = new OBC.SimpleCamera(components);
components.init();

2. IFC → Fragment 변환

const ifcLoader = components.get(OBC.IfcLoader);
await ifcLoader.setup();

const file = await fetch("model.ifc");
const buffer = new Uint8Array(await file.arrayBuffer());
const model = await ifcLoader.load(buffer);
world.scene.three.add(model);

3. 미리 만든 Fragment load (instant)

const fragments = components.get(OBC.FragmentsManager);
const data = await fetch("model.frag").then(r => r.arrayBuffer());
const group = fragments.load(new Uint8Array(data));
world.scene.three.add(group);

4. Property query (lazy)

const indexer = components.get(OBC.IfcRelationsIndexer);
await indexer.process(model);

// Get all walls
const walls = await indexer.getEntitiesByType(model, "IFCWALL");
for (const expressID of walls) {
  const props = await model.getProperties(expressID);
  console.log(props.Name.value);
}

5. Highlight on click

const highlighter = components.get(OBCF.Highlighter);
highlighter.setup({ world });

highlighter.events.select.onHighlight.add((selection) => {
  console.log("Selected fragments:", selection);
});

6. Section plane (clipper)

const clipper = components.get(OBC.Clipper);
clipper.enabled = true;
container.addEventListener("dblclick", () => clipper.create(world));

7. Streaming (large model)

const streamer = components.get(OBCF.IfcStreamer);
streamer.url = "https://cdn.example.com/fragments/";
streamer.world = world;

await streamer.load(
  await fetch("model-streamed.json").then(r => r.json()),
  true  // coordinate to origin
);

매 결정 기준

상황	Approach
Small model (< 50MB IFC)	직접 IfcLoader.load()
Medium (50-500MB)	사전 변환된 .frag file
Large (500MB+)	IfcStreamer (tile-based LOD)
Property-heavy query	IfcRelationsIndexer + cached
Mobile viewer	Fragment + simplified geometry

기본값: ThatOpen Components 2026 + Fragment 사전 변환 + property cache.

🔗 Graph

• 부모: BIM (Building Information Modeling) · IFC (Industry Foundation Classes)
• 변형: Speckle · xeokit · Forge Viewer
• 응용: Web BIM Viewer · Clash Detection · Facility Management
• Adjacent: Three.js · WASM · FlatBuffers

🤖 LLM 활용

언제: 매 web-based BIM viewer 매 build. 매 IFC model 매 browser 의 instant load 가 필요. 매 open-source 매 prefer (Forge 의 X). 언제 X: 매 desktop-only workflow (Revit/Navisworks 매 충분). 매 < 10MB model (overkill). 매 photorealistic render (use Unreal/Unity).

❌ 안티패턴

• IFC 매 매번 parse: 매 100MB IFC 매 user 마다 30초 wait. 매 backend 사전 변환 필수.
• Property 매 eager load: 매 모든 property 매 memory load → OOM. 매 lazy + query-on-demand.
• InstancedMesh 무시: 매 IFC 의 매 1000+ identical column 매 매 separate Mesh → 매 draw call 폭발.
• GlobalId 의 X: 매 Fragment internal ID 매 IFC GlobalId 와 매 different — 매 cross-system mapping 매 GlobalId 사용.

🧪 검증 / 중복

• Verified (ThatOpen/engine_components GitHub 2026-05, web-ifc 0.0.66+).
• 신뢰도 A (rapidly-evolving project — 매 minor API drift 가능).

🕓 Changelog

날짜	변경
2026-05-08	Phase 1
2026-05-10	Manual cleanup — ThatOpen Components 2026 API + Fragment streaming