feat: axis-and-section skeleton GLB and three.js viewer (Task 7-8, skeleton LOD)

build_skeleton.py sweeps the confirmed standard section (R6982 inner, 300 mm
lining, R7402 excavation, crown 6.615 m above road) along the centreline for
4+745..5+480, road = 계획고, ground = 지반고 band. Walls and invert are
approximations and recorded in meta. Verified: inner radius identity, crown
height, chord length 799.9 m for 4+700..5+500. Viewer uses three.js 0.160.0.

Co-Authored-By: Claude Haiku 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01A5Cun3RHQKna9qxE6ybZ4A

README.md

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+# 대산2터널 본선 3D 골격 (Code/3d-drawing)
+
+## 실행
+1. 이 폴더(`Code/3d-drawing`)에서 HTTP 서버를 엽니다. 예: `python3 -m http.server 8000`
+2. 브라우저에서 `http://localhost:8000/viewer/` 를 엽니다.
+   - `file://`로 열면 GLB를 불러올 수 없습니다.
+
+## 구성
+- `model/tunnel_skeleton.glb` : 중심선·표준단면 스윕 골격 (4+745 ~ 5+480)
+- `model/tunnel_skeleton_meta.json` : 범위, 출처, 근사 항목, 미완 항목
+- `data/` : 추출 중간 결과 (CSV, JSON)
+- `scripts/` : 추출·생성 스크립트 (재현 순서는 아래)
+- `viewer/index.html` : three.js 0.160.0 기반 뷰어 (jsDelivr CDN)
+
+## 재현 순서
+1. `inventory_dxf.py` → 2. `extract_alignment_plan.py` → 3. `extract_profile_gl.py` → 4. `dump_std_table.py` → 5. `build_skeleton.py <이 폴더>`
+
+## 한계 (반드시 읽을 것)
+- 2D 도면 재구성 골격이며 실측 모델이 아닙니다.
+- 측벽은 수직, 인버트 미모델링. 근사 항목은 meta JSON에 기록.
+- 4+700~4+745, 5+480~5+500은 [미확정]으로 제외.
+- 지보패턴별 구간(03-003~008)과 라이닝 구조도 상세(04-004~009)는 아직 반영하지 않음.

data/verify_skeleton.json

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+{
+  "inner_radius_max_dev_m": 8.881784197001252e-16,
+  "lining_thickness_crown_m": 0.3,
+  "crown_above_road_m (expect 6.615 at S=0 station 5000)": 6.615,
+  "road_z_4745_m": 50.62,
+  "road_z_5480_m": 67.311,
+  "plan_chord_length_total_m (4+700..5+500)": 799.905,
+  "station_range_modelled": "4745 .. 5480 (ring step 5.0 m, 148 rings)",
+  "glb_bytes": 470416,
+  "glb_reload_geometries": 5
+}

model/tunnel_skeleton_meta.json

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+{
+  "model": "tunnel_skeleton.glb",
+  "scope": "4745~5480 (4+745~5+480)",
+  "units": "m",
+  "origin_plan_xy": [
+    151090.911,
+    483688.46
+  ],
+  "sources": {
+    "centreline": "C0060302-001 CA-ALGN-STSM (side-tick midpoint)",
+    "road_grade_B": "C0060302-002 CR-TABL-TEX2 (계획고=노면)",
+    "GL_A": "C0060302-002 CR-TABL-TEX2 (지반고)",
+    "section": "C0060303-001 CS-TABL-TEX1/2, CS-CONC-MAJR, CS-EXCV"
+  },
+  "approximations": [
+    "walls vertical down to road; invert not modelled",
+    "lining band thickness at walls is radial-consistent but not as-built",
+    "centreline and grade linearly interpolated between nodes",
+    "superelevation sign convention assumed (z += S/100 * x, x = left of tangent)"
+  ],
+  "layers": [
+    "lining_outer_R7282",
+    "lining_inner_R6982",
+    "excavation_R7402",
+    "road_surface_계획고",
+    "ground_GL_지반고"
+  ],
+  "open": [
+    "4+700~4+745 and 5+480~5+500 excluded ([미확정])",
+    "pattern zones (03-003~008) pending Task 5",
+    "lining details (04-004~009) pending Task 6"
+  ]
+}

scripts/build_skeleton.py

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+#!/usr/bin/env python3
+"""Task 7: axis + standard-section sweep skeleton of the main line (본선), 4+745..5+480.
+
+Inputs (all confirmed by the user, 2026-10-21):
+  - centreline nodes  data/alignment_plan_001_centre.csv   (midpoint of side ticks)
+  - profile           data/profile_gl_002_draft.csv        (A = 지반고 GL, B = 계획고 = 노면)
+  - section table     DOC/03_설계/설계_표준단면치수표_2026-10-21_v0.1.00.md
+      R1 6,982 mm (lining inner), lining 300 mm -> outer R 7,282, excavation R 7,402
+      crown A = 6.615 m above road (F = 0.000 = road reference)
+  - cross slope: 4+745~5+105 -2 %, 5+105~5+165 linear -2 -> +2 %, 5+165~5+480 +2 %
+Model (skeleton, not as-built):
+  - Section = arch (concentric centre c = 6.615 - 6.982) + vertical walls down to the road.
+    Walls and invert are APPROXIMATIONS and are flagged in the metadata. No invert.
+  - Superelevation: z += (S/100) * x across the section (sign convention ASSUMED, flagged).
+  - Coordinates: plan XY in m (station spacing 100 m matches plan units), origin at 4+745.
+Outputs: model/tunnel_skeleton.glb, model/tunnel_skeleton_meta.json, data/verify_skeleton.json
+"""
+import csv
+import json
+import math
+import sys
+
+import numpy as np
+import trimesh
+
+ROOT = sys.argv[1]  # Code/3d-drawing
+C_CSV = f"{ROOT}/data/alignment_plan_001_centre.csv"
+P_CSV = f"{ROOT}/data/profile_gl_002_draft.csv"
+R1, R_OUT, R_EX = 6.982, 7.282, 7.402           # m (mm / 1000)
+CROWN_A = 6.615                                  # m above road
+CENTRE_C = CROWN_A - R1                          # arch centre height above road (m)
+S0, S1 = 4745, 5480                              # modelled range (fully determined)
+DS = 5.0                                         # station step for rings (m)
+ANG = np.radians(np.linspace(40.0, 140.0, 41))   # arch arc, right springline -> left
+
+def read_centre():
+    rows = [r for r in csv.DictReader(open(C_CSV, encoding="utf-8"))]
+    return np.array([[int(r["station_m"]), float(r["centre_x"]), float(r["centre_y"])] for r in rows])
+
+def read_profile():
+    gl, dg = {}, {}
+    for r in csv.DictReader(open(P_CSV, encoding="utf-8")):
+        sta = int(r["station_anchor"])
+        (gl if float(r["across_m"]) < -25 else dg)[sta] = float(r["value"])
+    return gl, dg
+
+def slope_pct(s):
+    if s < 5105: return -2.0
+    if s < 5165: return -2.0 + 4.0 * (s - 5105) / 60.0
+    return 2.0
+
+cn = read_centre()
+gl_d, dg_d = read_profile()
+gl_s = np.array(sorted(gl_d)); gl_v = np.array([gl_d[k] for k in gl_s])
+dg_s = np.array(sorted(dg_d)); dg_v = np.array([dg_d[k] for k in dg_s])
+cn_s = cn[:, 0]
+
+def axis_xy(s):
+    x = np.interp(s, cn_s, cn[:, 1]); y = np.interp(s, cn_s, cn[:, 2])
+    i = min(max(np.searchsorted(cn_s, s) - 1, 0), len(cn_s) - 2)
+    dx, dy = cn[i + 1, 1] - cn[i, 1], cn[i + 1, 2] - cn[i, 2]
+    L = math.hypot(dx, dy)
+    return x, y, dx / L, dy / L
+
+ORIGIN = np.array(axis_xy(S0)[:2])
+stations = np.arange(S0, S1 + 0.001, DS)
+
+def section(R, s, slope):
+    """ring (x lateral m, z above road m) for radius R, including superelevation."""
+    xs = np.concatenate([[R * math.cos(ANG[0])], R * np.cos(ANG), [R * math.cos(ANG[-1])]])
+    zs = np.concatenate([[0.0], CENTRE_C + R * np.sin(ANG), [0.0]])
+    zs = zs + slope * xs
+    return xs, zs
+
+def ring_world(R, s):
+    x, y, tx, ty = axis_xy(s)
+    nx, ny = -ty, tx                           # left normal (horizontal)
+    zr = np.interp(s, dg_s, dg_v)              # road (계획고 = 노면)
+    xs, zs = section(R, s, slope_pct(s) / 100.0)
+    P = np.column_stack([x - ORIGIN[0] + xs * nx, y - ORIGIN[1] + xs * ny, zr + zs])
+    return P
+
+def make_band(R, color, name):
+    rings = [ring_world(R, s) for s in stations]
+    n = len(rings[0]); m = len(rings)
+    V = np.vstack(rings)
+    F = []
+    for i in range(m - 1):
+        for j in range(n - 1):
+            a = i * n + j; b = a + 1; c = a + n; d = c + 1
+            F += [[a, b, c], [b, d, c]]
+    mesh = trimesh.Trimesh(vertices=V, faces=np.array(F), process=False)
+    mesh.visual.face_colors = np.tile(np.array(color, dtype=np.uint8), (len(F), 1))
+    mesh.metadata["name"] = name
+    return mesh
+
+def make_ribbon(z_fn, half_w, color, name):
+    V, F = [], []
+    for k, s in enumerate(stations):
+        x, y, tx, ty = axis_xy(s)
+        nx, ny = -ty, tx
+        zr = z_fn(s)
+        V.append([x - ORIGIN[0] - half_w * nx, y - ORIGIN[1] - half_w * ny, zr])
+        V.append([x - ORIGIN[0] + half_w * nx, y - ORIGIN[1] + half_w * ny, zr])
+    V = np.array(V)
+    for k in range(len(stations) - 1):
+        a = 2 * k; b = a + 1; c = a + 2; d = a + 3
+        F += [[a, c, b], [b, c, d]]
+    mesh = trimesh.Trimesh(vertices=V, faces=np.array(F), process=False)
+    mesh.visual.face_colors = np.tile(np.array(color, dtype=np.uint8), (len(F), 1))
+    mesh.metadata["name"] = name
+    return mesh
+
+parts = [
+    make_band(R_OUT, (190, 190, 186, 255), "lining_outer_R7282"),
+    make_band(R1,    (235, 235, 230, 255), "lining_inner_R6982"),
+    make_band(R_EX,  (150, 120, 90, 110),  "excavation_R7402"),
+    make_ribbon(lambda s: float(np.interp(s, dg_s, dg_v)), 5.0, (70, 70, 75, 255), "road_surface_계획고"),
+    make_ribbon(lambda s: float(np.interp(s, gl_s, gl_v)), 20.0, (110, 150, 90, 200), "ground_GL_지반고"),
+]
+scene = trimesh.Scene()
+for p in parts:
+    scene.add_geometry(p, geom_name=p.metadata["name"])
+glb = f"{ROOT}/model/tunnel_skeleton.glb"
+scene.export(glb)
+
+# ---- verification (assertions recorded, not forced) ----
+checks = {}
+# radius check in section plane: distance from arch centre (lateral=0, z=centre_c)
+xs, zs = section(R1, S0, 0.0)
+rad = np.hypot(xs[1:-1], zs[1:-1] - CENTRE_C)
+checks["inner_radius_max_dev_m"] = float(np.max(np.abs(rad - R1)))
+checks["lining_thickness_crown_m"] = round(R_OUT - R1, 3)
+crown_z = ring_world(R1, 5000)[:, 2].max() - np.interp(5000, dg_s, dg_v)
+checks["crown_above_road_m (expect 6.615 at S=0 station 5000)"] = round(float(crown_z), 4)
+checks["road_z_4745_m"] = round(float(np.interp(S0, dg_s, dg_v)), 3)
+checks["road_z_5480_m"] = round(float(np.interp(S1, dg_s, dg_v)), 3)
+L_chord = float(np.sum([math.dist(cn[i, 1:], cn[i + 1, 1:]) for i in range(len(cn) - 1)]))
+checks["plan_chord_length_total_m (4+700..5+500)"] = round(L_chord, 3)
+checks["station_range_modelled"] = f"{S0} .. {S1} (ring step {DS} m, {len(stations)} rings)"
+checks["glb_bytes"] = int(__import__("os").path.getsize(glb))
+reload = trimesh.load(glb)
+checks["glb_reload_geometries"] = len(reload.geometry)
+json.dump(checks, open(f"{ROOT}/data/verify_skeleton.json", "w", encoding="utf-8"), ensure_ascii=False, indent=2)
+meta = {
+  "model": "tunnel_skeleton.glb", "scope": f"{S0}~{S1} (4+745~5+480)",
+  "units": "m", "origin_plan_xy": [round(ORIGIN[0], 3), round(ORIGIN[1], 3)],
+  "sources": {"centreline": "C0060302-001 CA-ALGN-STSM (side-tick midpoint)",
+              "road_grade_B": "C0060302-002 CR-TABL-TEX2 (계획고=노면)",
+              "GL_A": "C0060302-002 CR-TABL-TEX2 (지반고)",
+              "section": "C0060303-001 CS-TABL-TEX1/2, CS-CONC-MAJR, CS-EXCV"},
+  "approximations": ["walls vertical down to road; invert not modelled",
+                     "lining band thickness at walls is radial-consistent but not as-built",
+                     "centreline and grade linearly interpolated between nodes",
+                     "superelevation sign convention assumed (z += S/100 * x, x = left of tangent)"],
+  "layers": [p.metadata["name"] for p in parts],
+  "open": ["4+700~4+745 and 5+480~5+500 excluded ([미확정])", "pattern zones (03-003~008) pending Task 5",
+           "lining details (04-004~009) pending Task 6"]
+}
+json.dump(meta, open(f"{ROOT}/model/tunnel_skeleton_meta.json", "w", encoding="utf-8"), ensure_ascii=False, indent=2)
+print(json.dumps(checks, ensure_ascii=False, indent=1))

viewer/index.html

@@ -0,0 +1,126 @@
+<!doctype html>
+<html lang="ko">
+<head>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width,initial-scale=1">
+<title>대산2터널 본선 3D 골격</title>
+<style>
+:root{--bg:#f6f6f4;--fg:#1d1d1b;--panel:rgba(255,255,255,.92);--line:#d7d7d2;--accent:#2f6f6a}
+@media (prefers-color-scheme: dark){:root:not([data-theme="light"]){--bg:#15171a;--fg:#e9e9e6;--panel:rgba(31,34,38,.92);--line:#3a3f46;--accent:#6fb7b0}}
+:root[data-theme="dark"]{--bg:#15171a;--fg:#e9e9e6;--panel:rgba(31,34,38,.92);--line:#3a3f46;--accent:#6fb7b0}
+html,body{margin:0;height:100%;background:var(--bg);color:var(--fg);font-family:system-ui,"Noto Sans KR",sans-serif;overflow:hidden}
+#app{position:fixed;inset:0}
+#panel{position:absolute;left:12px;top:12px;width:300px;max-width:calc(100vw - 24px);background:var(--panel);border:1px solid var(--line);border-radius:10px;padding:12px 14px;font-size:14px;box-sizing:border-box}
+#panel h1{font-size:16px;margin:0 0 8px;color:var(--accent)}
+#toggles label{display:flex;gap:6px;align-items:center;margin:4px 0;font-size:13px}
+#info{white-space:pre-wrap;font-size:12px;line-height:1.5;margin-top:10px;border-top:1px solid var(--line);padding-top:8px;max-height:38vh;overflow:auto}
+#status{position:absolute;right:12px;bottom:12px;font-size:12px;background:var(--panel);padding:4px 8px;border-radius:6px;border:1px solid var(--line)}
+</style>
+<script type="importmap">
+{"imports":{"three":"https://cdn.jsdelivr.net/npm/three@0.160.0/build/three.module.js","three/addons/":"https://cdn.jsdelivr.net/npm/three@0.160.0/examples/jsm/"}}
+</script>
+</head>
+<body>
+<div id="app"></div>
+<div id="panel">
+  <h1>대산2터널 본선 3D 골격</h1>
+  <div id="toggles"></div>
+  <div id="info">로딩 중입니다. 모델을 클릭하면 요소 정보가 표시됩니다.</div>
+</div>
+<div id="status">로딩 중…</div>
+<script type="module">
+import * as THREE from 'three';
+import { GLTFLoader } from 'three/addons/loaders/GLTFLoader.js';
+import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
+
+const MODEL = '../model/tunnel_skeleton.glb';
+const META = '../model/tunnel_skeleton_meta.json';
+const INFO = {
+  'lining_outer_R7282': '라이닝 외면 R 7.282 m\n출처: C0060303-001 CS-CONC-MAJR (R7282 호), 라이닝 두께 300 mm',
+  'lining_inner_R6982': '라이닝 내면 R 6.982 m (R1)\n출처: C0060303-001 상단 변수표 R1 = 6,982 mm',
+  'excavation_R7402': '굴착선 R 7.402 m (반투명)\n출처: C0060303-001 CS-EXCV 호',
+  'road_surface_계획고': '노면 (계획고)\n출처: C0060302-002 CR-TABL-TEX2 B열. 계획고 = 노면, F = 0.000 기준',
+  'ground_GL_지반고': '지반고 (GL, 개략 표시)\n출처: C0060302-002 CR-TABL-TEX2 A열. 중심선 양측 ±20 m 띠로 표시'
+};
+const status = document.getElementById('status');
+const info = document.getElementById('info');
+const togglesEl = document.getElementById('toggles');
+
+const dark = matchMedia('(prefers-color-scheme: dark)').matches;
+const renderer = new THREE.WebGLRenderer({ antialias: true });
+renderer.setPixelRatio(Math.min(devicePixelRatio, 2));
+renderer.setSize(innerWidth, innerHeight);
+document.getElementById('app').appendChild(renderer.domElement);
+const scene = new THREE.Scene();
+scene.background = new THREE.Color(dark ? 0x15171a : 0xf6f6f4);
+const camera = new THREE.PerspectiveCamera(45, innerWidth / innerHeight, 0.1, 20000);
+const controls = new OrbitControls(camera, renderer.domElement);
+controls.enableDamping = true;
+scene.add(new THREE.HemisphereLight(0xffffff, 0x556070, 1.0));
+const sun = new THREE.DirectionalLight(0xffffff, 0.8);
+sun.position.set(1, 2, 1);
+scene.add(sun);
+
+const meshes = [];
+const loader = new GLTFLoader();
+loader.load(MODEL, (gltf) => {
+  const root = gltf.scene;
+  scene.add(root);
+  root.traverse((o) => {
+    if (o.isMesh) {
+      const name = o.name || (o.parent && o.parent.name) || 'unnamed';
+      o.userData.key = name;
+      o.material.side = THREE.DoubleSide;
+      if (/excavation|ground/.test(name)) { o.material.transparent = true; o.material.opacity = 0.55; o.material.depthWrite = false; }
+      meshes.push(o);
+    }
+  });
+  const box = new THREE.Box3().setFromObject(root);
+  const c = box.getCenter(new THREE.Vector3());
+  const s = box.getSize(new THREE.Vector3());
+  const d = Math.max(s.x, s.y, s.z);
+  controls.target.copy(c);
+  camera.position.set(c.x + d * 0.6, c.y + d * 0.5, c.z + d * 0.9);
+  camera.near = d / 1000; camera.far = d * 20; camera.updateProjectionMatrix();
+  const names = [...new Set(meshes.map((m) => m.userData.key))];
+  for (const n of names) {
+    const lab = document.createElement('label');
+    const cb = document.createElement('input');
+    cb.type = 'checkbox'; cb.checked = true;
+    cb.addEventListener('change', () => meshes.filter((m) => m.userData.key === n).forEach((m) => (m.visible = cb.checked)));
+    lab.append(cb, document.createTextNode(n));
+    togglesEl.appendChild(lab);
+  }
+  status.textContent = '로드 완료 · 요소 ' + names.length + '종';
+}, undefined, () => {
+  status.textContent = '로드 실패: 파일을 HTTP 서버로 여세요 (README 참조)';
+});
+
+fetch(META).then((r) => r.json()).then((m) => {
+  info.textContent = '범위: ' + m.scope + ' (단위 ' + m.units + ')\n근사 항목:\n- ' + m.approximations.join('\n- ') + '\n미완:\n- ' + m.open.join('\n- ');
+}).catch(() => {});
+
+const ray = new THREE.Raycaster();
+const ptr = new THREE.Vector2();
+let downAt = null;
+renderer.domElement.addEventListener('pointerdown', (e) => { downAt = [e.clientX, e.clientY]; });
+renderer.domElement.addEventListener('pointerup', (e) => {
+  if (!downAt || Math.hypot(e.clientX - downAt[0], e.clientY - downAt[1]) > 4) return;
+  const r = renderer.domElement.getBoundingClientRect();
+  ptr.set(((e.clientX - r.left) / r.width) * 2 - 1, -((e.clientY - r.top) / r.height) * 2 + 1);
+  ray.setFromCamera(ptr, camera);
+  const hit = ray.intersectObjects(meshes.filter((m) => m.visible), false)[0];
+  if (hit) {
+    const key = hit.object.userData.key;
+    info.textContent = (INFO[key] || key) + '\n교차점: x=' + hit.point.x.toFixed(2) + ' y=' + hit.point.y.toFixed(2) + ' z=' + hit.point.z.toFixed(2) + ' (m, 모델 좌표)';
+  }
+});
+
+addEventListener('resize', () => {
+  camera.aspect = innerWidth / innerHeight; camera.updateProjectionMatrix();
+  renderer.setSize(innerWidth, innerHeight);
+});
+renderer.setAnimationLoop(() => { controls.update(); renderer.render(scene, camera); });
+</script>
+</body>
+</html>