fix(abut): 날개벽 헌치를 내측면 기준으로 재배치

- 뒷굽 헌치 삭제
- 연직 헌치 2개(흉벽 배면, 벽체 배면)를 날개벽 내측면 모서리에 평면 삼각형 기둥으로 둠
- 저판 상면 헌치 추가: 저판 상면과 날개벽 내측면 사이의 수평 헌치 (벽체 배면 → 뒷굽 구간, 다리 0.3 m)
- 테스트 갱신 (헌치 6개, 저판 상면 헌치 범위). 전체 639건 통과, 타입 검사·빌드 통과. 브라우저 시각 확인은 미실시

Co-Authored-By: Claude Haiku 5.5 <noreply@anthropic.com>

src/core/abut/wings.ts

@@ -41,10 +41,10 @@ export interface WingSolid {
   /** 헌치 300 × 300 (위 헌치, 흉벽 배면 모서리). 평면 삼각형과 높이 범위. */
   haunches: Haunch[];
   /**
-   * 뒷굽 헌치 (삽도, 날개벽과 확대기초): (t, EL) 직각삼각형. 꼭짓점은 뒷굽 끝 H, 날개벽 하면을 따라 0.3 m, 뒷굽 면을 따라 아래로 0.3 m.
-   * 날개벽 두께(0.45 m)만큼 s 방향으로 민다. 단축형 날개벽에는 없다.
+   * 저판 상면 헌치 (수평, 2026-11-03): between the 저판 상면 and the 날개벽 내측면. The triangle lies in the plane EL–s,
+   * with legs HAUNCH_LEG_M along the 저판 상면 and along the 내측면; it runs along the wing from dMFrom (벽체 배면) to dMTo (뒷굽).
    */
-  heelHaunch?: [number, number][];
+  footingHaunch?: { dMFrom: number; dMTo: number; el: number };
   /** 수평 단 (QA-12, spec_abut §4.7): 등단면 / 변화단면1 / 변화단면2. 경계는 단부 높이 1.5 m와 교좌면 EL. */
   bands: WingBand[];
 }
@@ -130,23 +130,15 @@ export function buildWings(model: AbutModel, members: AbutMembers, forms?: { lef
         zTopEl: kind === 'upper' ? topAt(d) : bracketTop,
       };
     };
-    const haunches = [haunchAt('upper', members.shape.parapetBackM)];
+    // 연직 헌치 (2026-11-03, 내측면 모서리): upper at the 흉벽 배면, lower at the 벽체 배면.
+    const haunches = [haunchAt('upper', members.shape.parapetBackM), haunchAt('lower', members.shape.wallBackM)];
 
-    // 뒷굽 헌치 (삽도): at the heel H = (footing back, footing top). The 300 legs run along the wing underside and down the 뒷굽 face.
-    const tOf = (dM: number) => (members.shape.footingBackM * dM) / heelDistanceM;
-    const underside = bottomLine.find((p) => p.dM > heelDistanceM + 1e-9);
-    const heelHaunch: [number, number][] | undefined =
-      underside === undefined
-        ? undefined
-        : (() => {
-            const H: [number, number] = [members.shape.footingBackM, footingTop];
-            const ux = tOf(underside.dM) - H[0];
-            const uy = underside.el - H[1];
-            const len = Math.hypot(ux, uy);
-            const A: [number, number] = [H[0] + (0.3 * ux) / len, H[1] + (0.3 * uy) / len];
-            const B: [number, number] = [H[0], H[1] - 0.3];
-            return [H, A, B];
-          })();
+    // 저판 상면 헌치 (수평): from the 벽체 배면 to the 뒷굽, on the 저판 상면 next to the 날개벽 내측면.
+    const footingHaunch = {
+      dMFrom: Math.abs(members.shape.wallBackM) / k,
+      dMTo: heelDistanceM,
+      el: footingTop,
+    };
 
     // 수평 단 (QA-12): 등단면 = 끝 상단 − 1.5 m 위, 변화단면1 = 그 아래 ~ 교좌면 EL, 변화단면2 = 교좌면 EL ~ 저판 상면.
     // 교좌면 EL은 날개벽 끝에 가장 가까운 받침의 교좌면이다.
@@ -172,7 +164,7 @@ export function buildWings(model: AbutModel, members: AbutMembers, forms?: { lef
       topLine,
       bottomLine,
       haunches,
-      heelHaunch,
+      footingHaunch,
       bands,
     };
   };

src/view/abut-scene.ts

@@ -8,7 +8,7 @@
 import * as THREE from 'three';
 import type { AbutModel, AbutPoint } from '../core/abut/geometry';
 import { buildMembers, type AbutMembers } from '../core/abut/members';
-import { buildWings, WING_THICKNESS_M, type WingSolid } from '../core/abut/wings';
+import { buildWings, HAUNCH_LEG_M, WING_THICKNESS_M, type WingSolid } from '../core/abut/wings';
 import type { TerrainGrid } from '../core/ground-model';
 import { terrainGeometry } from './terrain';
 
@@ -284,10 +284,14 @@ export function buildAbutGroup(
     const lower = prism(clipBelowX(below, members.shape.wallBackM / dir.wt), WING_THICKNESS_M, new THREE.Vector3(sEnd, 0, 0), ax, ey, new THREE.Vector3(a, 0, 0));
     add('wings', upper, 0xc9a77c);
     add('wings', lower, 0xc9a77c);
-    // 뒷굽 헌치 (삽도): (t, EL) triangle, extruded across the wing thickness along s.
-    if (wing.heelHaunch) {
-      const profile = wing.heelHaunch;
-      add('haunches', prism(profile, WING_THICKNESS_M, new THREE.Vector3(sEnd, 0, 0), ez, ey, new THREE.Vector3(a, 0, 0)), 0xc9a77c);
+    // 저판 상면 헌치 (수평, 2026-11-03): a right triangle in the plane EL–s on the 저판 상면, next to the 날개벽 내측면,
+    // extruded along the wing from the 벽체 배면 to the 뒷굽.
+    if (wing.footingHaunch) {
+      const f = wing.footingHaunch;
+      const leg = HAUNCH_LEG_M;
+      const triangle: [number, number][] = [[0, 0], [leg, 0], [0, leg]];
+      const origin = new THREE.Vector3(sEnd + a * WING_THICKNESS_M + dir.ws * f.dMFrom, f.el, dir.wt * f.dMFrom);
+      add('haunches', prism(triangle, f.dMTo - f.dMFrom, origin, new THREE.Vector3(a, 0, 0), ey, new THREE.Vector3(dir.ws, 0, dir.wt)), 0xc9a77c);
     }
     for (const h of wing.haunches) {
       const shape: [number, number][] = h.corners.map((c) => {

tests/abut-scene.test.ts

@@ -21,13 +21,13 @@ const group = buildAbutGroup(model, members, wings);
 const count = (name: string) => (group.getObjectByName(name) as THREE.Group | undefined)?.children.length ?? 0;
 
 describe('교대 A1 3D 장면 (AA3·AA3b·AA3c)', () => {
-  it('has the members: 5 wall blocks, 10 parapet parts (2 per step), 1 footing, 18 piles, 2 wings, 4 haunches', () => {
+  it('has the members: 5 wall blocks, 10 parapet parts (2 per step), 1 footing, 18 piles, 2 wings, 6 haunches', () => {
     expect(count('wall')).toBe(5); // one 벽체 block per 교좌면 step (삽도)
     expect(count('parapet')).toBe(10); // per step: back strip (흉벽 배면 단차) and the 흉벽 (삽도)
     expect(count('footing')).toBe(1);
     expect(count('piles')).toBe(18);
     expect(count('wings')).toBe(4); // upper and lower part per wing
-    expect(count('haunches')).toBe(4);
+    expect(count('haunches')).toBe(6); // per wing: upper and lower 연직 헌치, and the 저판 상면 헌치
   });
 
   it('spans from the pile tip (19.295 m) up to the highest parapet end (47.18 m)', () => {

tests/abut-wings.test.ts

@@ -117,24 +117,30 @@ describe('교대 날개벽 하단 선 · 헌치 (AA3c, spec_abut §4.7)', () =>
     expect(line[2].el).toBeCloseTo(45.214, 2);
   });
 
-  it('the upper 300 × 300 haunch sits at the 흉벽 배면 (legs 0.3 m); the 뒷굽 haunch is a (t, EL) triangle with 0.3 m legs at the heel', () => {
-    expect(a2Left.haunches.map((h) => h.kind)).toEqual(['upper']);
-    const tri = a2Left.heelHaunch!;
-    expect(tri).toHaveLength(3);
-    expect(tri[0][0]).toBeCloseTo(-1.8, 6); // 뒷굽 끝 (t)
-    expect(Math.hypot(tri[1][0] - tri[0][0], tri[1][1] - tri[0][1])).toBeCloseTo(0.3, 6);
-    expect(tri[2][1]).toBeCloseTo(tri[0][1] - 0.3, 6); // leg down the 뒷굽 face
-    const [c0, c1, c2] = a2Left.haunches[0].corners;
-    expect(Math.hypot(c1.e - c0.e, c1.n - c0.n)).toBeCloseTo(0.3, 6);
-    expect(Math.hypot(c2.e - c0.e, c2.n - c0.n)).toBeCloseTo(0.3, 6);
+  it('two vertical 300 × 300 haunches at the 내측면 corners: upper at the 흉벽 배면, lower at the 벽체 배면', () => {
+    expect(a2Left.haunches.map((h) => h.kind)).toEqual(['upper', 'lower']);
+    for (const h of a2Left.haunches) {
+      const [c0, c1, c2] = h.corners;
+      expect(Math.hypot(c1.e - c0.e, c1.n - c0.n)).toBeCloseTo(0.3, 6);
+      expect(Math.hypot(c2.e - c0.e, c2.n - c0.n)).toBeCloseTo(0.3, 6);
+    }
+  });
+
+  it('the 저판 상면 haunch runs from the 벽체 배면 to the 뒷굽 on the 저판 상면; the 뒷굽 haunch is gone', () => {
+    const f = a2Left.footingHaunch!;
+    expect(f.el).toBeCloseTo(41.995, 3);
+    expect(f.dMTo).toBeGreaterThan(f.dMFrom);
+    expect((a2Left as { heelHaunch?: unknown }).heelHaunch).toBeUndefined();
   });
 
   it('upper haunch runs from the bracket top (흉벽 상단 − 0.85) to the wing top', () => {
-    const [up] = a2Left.haunches;
+    const [up, low] = a2Left.haunches;
     // The upper haunch rests on the highest point of the 브라켓 top over its footprint (the top falls along s), never below it.
     expect(up.zBottomEl).toBeGreaterThanOrEqual(46.838 - 0.85 - 1e-6);
     expect(up.zBottomEl).toBeLessThan(46.838 - 0.85 + 0.05);
     expect(up.zTopEl).toBeGreaterThan(up.zBottomEl);
+    expect(low.zBottomEl).toBeCloseTo(41.995, 3);
+    expect(low.zTopEl).toBeCloseTo(46.838 - 0.85, 2);
   });
 });