diff --git a/B05_Profile/B05_Profile_UI_Corridor_Modes.ts b/B05_Profile/B05_Profile_UI_Corridor_Modes.ts
index fd91d5a7c..c613cbfec 100644
--- a/B05_Profile/B05_Profile_UI_Corridor_Modes.ts
+++ b/B05_Profile/B05_Profile_UI_Corridor_Modes.ts
@@ -17,6 +17,7 @@ import type { TerrainHeightIndex } from "./B05_Profile_UI_Corridor_Terrain";
 import type { TerrainBandSplit } from "./B05_Profile_UI_Corridor_Split";
 import { buildPatchSkirts } from "./B05_Profile_UI_Corridor_Skirt";
 import { deformTerrain } from "./B05_Profile_UI_Corridor_Deform_Terrain";
+import { tinTerrain } from "./B05_Profile_UI_Corridor_Tin";
 import { legacyCorridorOf, legacyReady } from "./B05_Profile_UI_Corridor_Legacy";
 import { readStateRaw, writeStateRaw } from "../A00_Common/b_page_state";
 
@@ -156,7 +157,13 @@ export const CORRIDOR_MODES: CorridorMode[] = [
     terrain: ({ split, build, bounds, heightIndex }) =>
       heightIndex ? deformTerrain(split, build, bounds, heightIndex) : null,
   },
-  // 제안 ② — 다른 창이 여기 한 줄: { id: "proposal2", corridor: …, terrain: … },
+  // 제안 ②(115-6) — 노면부만 그리고 비탈 · 지형 이음은 단일 삼각망(TIN).
+  {
+    id: "proposal2",
+    corridor: (build) => roadOnly(build),
+    terrain: ({ split, build, bounds, heightIndex }) =>
+      heightIndex ? tinTerrain(split, build, bounds, heightIndex) : null,
+  },
 ];
 
 export function modeOf(id: CorridorModeId): CorridorMode | null {
diff --git a/resources/tester/helper_115_6_corridor_tin.cjs b/resources/tester/helper_115_6_corridor_tin.cjs
index 9f7ed3f25..b1aa8229b 100644
--- a/resources/tester/helper_115_6_corridor_tin.cjs
+++ b/resources/tester/helper_115_6_corridor_tin.cjs
@@ -554,4 +554,17 @@ const r6 = (v) => Math.round(v * 1e6) / 1e6;
   results.berm = { stats: out.stats, missing, sectionErr: r6(sectionErr), gaps: gap.gaps };
 }
 
+// ⑤ 3D 방식 등록부(115-5) — 「제안 ②」 자리에 TIN 지형이 등록됐나.
+{
+  globalThis.window = globalThis.window || {};
+  const Modes = loadTs(B05("B05_Profile_UI_Corridor_Modes"));
+  const mode = Modes.modeOf("proposal2");
+  results.registry = {
+    slot: Modes.MODE_SLOTS.some(([id]) => id === "proposal2"),
+    registered: Boolean(mode),
+    hasTerrain: typeof mode?.terrain === "function",
+    noIndex: mode?.terrain ? mode.terrain({ heightIndex: null }) : "none",
+  };
+}
+
 process.stdout.write(JSON.stringify(results));
diff --git a/resources/tester/test_115_6_corridor_tin.py b/resources/tester/test_115_6_corridor_tin.py
index 2eb65b456..e0ad94d7d 100644
--- a/resources/tester/test_115_6_corridor_tin.py
+++ b/resources/tester/test_115_6_corridor_tin.py
@@ -73,6 +73,13 @@ def test_berm_bend_lines(results):
     assert r["gaps"] == 0
 
 
+def test_registered_as_proposal2(results):
+    r = results["registry"]
+    assert r["slot"] is True
+    assert r["registered"] is True and r["hasTerrain"] is True
+    assert r["noIndex"] is None  # 높이 색인 없으면 다른 방식(띠 자르기)으로
+
+
 def test_dependencies_two_only():
     with open(os.path.join(ROOT, "config", "package.json"), encoding="utf-8") as f:
         deps = json.load(f)["dependencies"]