diff --git a/E04_Stab3D/E04_Stab3D_Run.py b/E04_Stab3D/E04_Stab3D_Run.py
index 8ffc5fbb7..299ca5ca5 100644
--- a/E04_Stab3D/E04_Stab3D_Run.py
+++ b/E04_Stab3D/E04_Stab3D_Run.py
@@ -33,7 +33,7 @@ from E03_StabSection.E03_StabSection_Types import DEFAULT_ROAD_SURCHARGE_KPA
 from E04_Stab3D import E04_Stab3D_Engine_Grid as grid_engine
 from E04_Stab3D import E04_Stab3D_Engine_Search as search_engine
 
-ENGINE_VERSION = "e04-1"  # 엔진 판 — 바뀌면 지문이 달라져 다시 셈
+ENGINE_VERSION = "e04-2"  # 엔진 판 — 바뀌면 지문이 달라져 다시 셈
 STAGE_DIR = "E04_Stab3D"
 GROUND_FILE = Path("E02_StabGround") / "ground.json"
 SECTION_LENGTH_M = 100.0  # 자동 구간 길이
@@ -129,7 +129,8 @@ def _engine_station(root: Path, station: dict[str, Any]) -> dict[str, Any]:
 def _node_mask(
     root: Path, grid: dict[str, Any], start_m: float, end_m: float, half_width_m: float
 ) -> np.ndarray:
-    """탐색 노드 자리 = 중심선에서 half_width 안 · 가장 가까운 중심선 점의 누가가 구간 안."""
+    """탐색 노드 자리 = 중심선에서 half_width 안 · 가장 가까운 중심선 점의 누가가 구간 안
+    · 가장 가까운 점이 노선 양 끝점인 셀(노선 시점 앞 · 종점 뒤)은 뺌."""
     points = sorted(
         source.db_snapshot(root).get("route_points") or [], key=lambda p: p["sequence_num"]
     )
@@ -145,6 +146,7 @@ def _node_mask(
     dist, at = cKDTree(line[:, :2]).query(np.column_stack([xx.ravel(), yy.ravel()]))
     chain = line[at, 2]
     keep = (dist <= half_width_m) & (chain >= start_m - 1e-6) & (chain <= end_m + 1e-6)
+    keep &= (at > 0) & (at < len(line) - 1)
     return keep.reshape(xx.shape)
 
 
diff --git a/E04_Stab3D/E04_Stab3D_UI_Map.ts b/E04_Stab3D/E04_Stab3D_UI_Map.ts
index 85b8d5ebe..407511ee3 100644
--- a/E04_Stab3D/E04_Stab3D_UI_Map.ts
+++ b/E04_Stab3D/E04_Stab3D_UI_Map.ts
@@ -7,7 +7,7 @@
 
 import { el } from "@ui/ui_template_elements";
 import { t } from "@ui/ui_template_locale";
-import { cutCells } from "./logic/E04_Stab3D_Mesh";
+import { cutCells, footprintCenter } from "./logic/E04_Stab3D_Mesh";
 import {
   FS_STEPS,
   VOLUME_STEPS,
@@ -40,6 +40,8 @@ interface View {
   scale: number; // px / m
 }
 
+const RANGE_COLOR = "#2563eb"; // 고른 구간 — 3D 노선 관과 같은 색 · 안전율 색 단계와 겹치지 않음
+
 const shortLabel = (label: string): string => label.replace(/^STA\./, "").replace(/\.0+$/, "");
 
 const css = (name: string, fallback: string): string =>
@@ -61,6 +63,7 @@ export function createPlanMap(): PlanMap {
   let layer: MapLayer = "fs";
   let image: HTMLCanvasElement | null = null;
   let outline: Set<number> = new Set();
+  let marker: { x: number; y: number } | null = null;
   let view: View = { cx: 0, cy: 0, scale: 1 };
   let width = 0;
   let height = 0;
@@ -118,7 +121,7 @@ export function createPlanMap(): PlanMap {
     if (line.length < 2) return;
     ctx.lineJoin = ctx.lineCap = "round";
     ctx.strokeStyle = text;
-    ctx.lineWidth = 2;
+    ctx.lineWidth = 1.5;
     ctx.beginPath();
     line.forEach((p, i) =>
       i ? ctx.lineTo(...toScreen(p[0], p[1])) : ctx.moveTo(...toScreen(p[0], p[1])),
@@ -184,9 +187,9 @@ export function createPlanMap(): PlanMap {
   }
 
   function drawMarker(text: string): void {
-    if (!result) return;
+    if (!result || !marker) return;
     const { best } = result;
-    const [px, py] = toScreen(best.x, best.y);
+    const [px, py] = toScreen(marker.x, marker.y);
     ctx.lineWidth = 2;
     ctx.strokeStyle = "#ffffff";
     ctx.beginPath();
@@ -245,7 +248,7 @@ export function createPlanMap(): PlanMap {
     ctx.setTransform(dpr, 0, 0, dpr, 0, 0);
     ctx.clearRect(0, 0, width, height);
     const text = css("--color-text", "#1f2937");
-    const accent = css("--color-primary", "#6d28d9");
+    const accent = RANGE_COLOR;
     if (result && image) {
       const g = result.grid;
       const [left, top] = toScreen(g.x0 - g.dx / 2, g.y0 + (g.ny - 0.5) * g.dx);
@@ -335,6 +338,8 @@ export function createPlanMap(): PlanMap {
       return { x: rect.left + px, y: rect.top + py };
     },
     result: () => result,
+    marker: () => marker,
+    outline: () => [...outline],
     layer: () => layer,
   };
   (window as unknown as { __e04Map?: typeof probe }).__e04Map = probe;
@@ -354,7 +359,9 @@ export function createPlanMap(): PlanMap {
     },
     setResult(next) {
       result = next;
-      outline = new Set(next ? cutCells(next.grid, next.z, next.best).keys() : []);
+      const cut = next ? cutCells(next.grid, next.z, next.best) : new Map<number, number>();
+      outline = new Set(cut.keys());
+      marker = next ? footprintCenter(next.grid, cut, next.best) : null;
       buildImage();
       fit();
       draw();
diff --git a/E04_Stab3D/E04_Stab3D_UI_Style.css b/E04_Stab3D/E04_Stab3D_UI_Style.css
index 7b0c9b7ca..f215ec07a 100644
--- a/E04_Stab3D/E04_Stab3D_UI_Style.css
+++ b/E04_Stab3D/E04_Stab3D_UI_Style.css
@@ -86,7 +86,7 @@
 
 .e04-map__empty {
   position: absolute;
-  inset: auto 0 45% 0;
+  inset: var(--spacing-16) 0 auto 0;
   margin: 0;
   text-align: center;
   color: var(--color-text-muted);
diff --git a/E04_Stab3D/logic/E04_Stab3D_Mesh.ts b/E04_Stab3D/logic/E04_Stab3D_Mesh.ts
index b191f4e79..66361007a 100644
--- a/E04_Stab3D/logic/E04_Stab3D_Mesh.ts
+++ b/E04_Stab3D/logic/E04_Stab3D_Mesh.ts
@@ -90,6 +90,22 @@ export function cutCells(
   return out;
 }
 
+/** 임계 활동체 평면 중심 = 잘린 셀 중심의 평균(없으면 구 중심) — 지도 최소 표시 자리 */
+export function footprintCenter(
+  grid: Grid,
+  cut: ReadonlyMap<number, number>,
+  best: SlipBest,
+): { x: number; y: number } {
+  if (!cut.size) return { x: best.x, y: best.y };
+  let sx = 0;
+  let sy = 0;
+  for (const index of cut.keys()) {
+    sx += grid.x0 + (index % grid.nx) * grid.dx;
+    sy += grid.y0 + Math.floor(index / grid.nx) * grid.dx;
+  }
+  return { x: sx / cut.size, y: sy / cut.size };
+}
+
 /** 잘린 셀의 8 이웃 중 잘리지 않은 셀(값 있음) — 활동면 테두리 */
 export function rimCells(
   grid: Grid,
diff --git a/resources/tester/test_533_3_e04_engine.py b/resources/tester/test_533_3_e04_engine.py
index 9e3497618..a3549dc85 100644
--- a/resources/tester/test_533_3_e04_engine.py
+++ b/resources/tester/test_533_3_e04_engine.py
@@ -178,3 +178,17 @@ def test_hooks_do_not_change_search():
     with pytest.raises(InterruptedError):
         search(strata, SearchParams(**base, should_stop=lambda: True))
     assert math.isfinite(plain.best["governing"])
+
+
+def test_node_mask_section_and_route_ends(root):
+    """노드 자리 = 구간 누가 안 · 탐색 폭 안 · 노선 시점 앞(x < 0) · 종점 뒤(x > 100)는 뺌."""
+    x = np.arange(-30.0, 131.0, 1.0)
+    y = np.arange(-20.0, 21.0, 1.0)
+    grid = {"x": x, "y": y}
+    mask = run._node_mask(root, grid, 0.0, 100.0, 12.0)
+    xx, yy = np.meshgrid(x, y)
+    assert not mask[xx < -0.5].any() and not mask[xx > 100.5].any()
+    assert not mask[np.abs(yy) > 12.0].any()
+    assert mask[(np.abs(yy) <= 12.0) & (xx >= 1) & (xx <= 99)].all()
+    part = run._node_mask(root, grid, 20.0, 60.0, 12.0)
+    assert not part[(xx < 19.5) | (xx > 60.5)].any() and part[(yy == 0) & (xx == 40)].all()
diff --git a/resources/tester/test_533_3_e04_logic.py b/resources/tester/test_533_3_e04_logic.py
index 380ba706a..b26ff6e6a 100644
--- a/resources/tester/test_533_3_e04_logic.py
+++ b/resources/tester/test_533_3_e04_logic.py
@@ -60,6 +60,8 @@ writeFileSync(process.argv[3], JSON.stringify({
   sphere: mesh(M.slipMesh(c.grid, c.z, c.sphere)),
   ellipsoid: mesh(M.slipMesh(c.grid, c.z, c.ellipsoid)),
   cut: Array.from(M.cutCells(c.grid, c.z, c.sphere).keys()),
+  center: M.footprintCenter(c.grid, M.cutCells(c.grid, c.z, c.sphere), c.sphere),
+  centerEmpty: M.footprintCenter(c.grid, new Map(), c.sphere),
   floored: Object.fromEntries(M.cutCells(c.grid, c.z,
     { ...c.sphere, floor: [[7 * 21 + 10, 53.0], [7 * 21 + 11, 60.0]] }).entries()),
   holed: mesh(M.terrainWithout(c.grid, c.z, M.cutCells(c.grid, c.z, c.sphere))),
@@ -180,6 +182,15 @@ def test_slip_mesh_vertices(ts, name):
     assert all(z < Z[i] for i, z in cut.items())
 
 
+def test_footprint_center(ts):
+    """지도 최소 표시 = 잘린 셀 중심 평균 · 잘린 셀 없으면 구 중심."""
+    cut = [i for i, _ in _py_cut(SPHERE)]
+    x = sum(GRID["x0"] + i % GRID["nx"] for i in cut) / len(cut)
+    y = sum(GRID["y0"] + i // GRID["nx"] for i in cut) / len(cut)
+    assert ts["center"] == pytest.approx({"x": x, "y": y})
+    assert ts["centerEmpty"] == {"x": SPHERE["x"], "y": SPHERE["y"]}
+
+
 def test_floor_truncates_slip(ts):
     """못 뚫는 층 — 활동면이 층 윗면 아래로 안 내려감 · 층이 지표보다 높으면 잘린 셀 아님."""
     center = 7 * 21 + 10