diff --git a/src/App.tsx b/src/App.tsx
index e6e16ee..ff06b71 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -609,6 +609,8 @@ export default function App() {
   const setSelectedColumnIds = useStore((s) => s.setSelectedColumnIds);
   const selectedColumnId =
     selectedColumnIds.length === 1 ? selectedColumnIds[0] : null;
+  const selectedContextObjectIds = useStore((s) => s.selectedContextObjectIds);
+  const setSelectedContextObjectIds = useStore((s) => s.setSelectedContextObjectIds);
 
   // ── Kontextmenüs (transienter UI-State, bleibt lokal) ─────────────────────
   // Eigenschaften-Zwischenablage des Ebenen-Kontextmenüs (Farbe + Linienstärke).
@@ -1905,7 +1907,8 @@ export default function App() {
         selectedRoomIds.length ||
         selectedExtrudedSolidIds.length ||
         selectedColumnIds.length ||
-        selectedRoofIds.length
+        selectedRoofIds.length ||
+        selectedContextObjectIds.length
       ) {
         const dids = new Set(selectedDrawingIds);
         const wids = new Set(selectedWallIds);
@@ -1916,6 +1919,7 @@ export default function App() {
         const exids = new Set(selectedExtrudedSolidIds);
         const colids = new Set(selectedColumnIds);
         const rfids = new Set(selectedRoofIds);
+        const ctxids = new Set(selectedContextObjectIds);
         setProject((p) => ({
           ...p,
           drawings2d: p.drawings2d.filter((d) => !dids.has(d.id)),
@@ -1931,6 +1935,7 @@ export default function App() {
           openings: (p.openings ?? []).filter(
             (o) => !oids.has(o.id) && !wids.has(o.hostWallId),
           ),
+          context: (p.context ?? []).filter((o) => !ctxids.has(o.id)),
         }));
         setSelectedDrawingIds([]);
         setSelectedWallIds([]);
@@ -1941,6 +1946,7 @@ export default function App() {
         setSelectedExtrudedSolidIds([]);
         setSelectedColumnIds([]);
         setSelectedRoofIds([]);
+        setSelectedContextObjectIds([]);
         setSelectedSectionLineId(null);
         e.preventDefault();
       }
@@ -1958,6 +1964,7 @@ export default function App() {
     selectedExtrudedSolidIds,
     selectedColumnIds,
     selectedRoofIds,
+    selectedContextObjectIds,
     selectedSectionLineId,
     project.walls,
     project.drawings2d,
@@ -3531,6 +3538,7 @@ export default function App() {
       },
       // ── Site-/Kontext-Schicht ──────────────────────────────────────────────
       contextObjects: project.context ?? [],
+      selectedContextObjectIds,
       onAddContextObjects: addContextObjectsAndFit,
       onRemoveContextObject: removeContextObject,
       onGenerateTerrain: generateTerrain,
@@ -3555,6 +3563,7 @@ export default function App() {
           setSelectedExtrudedSolidIds([]);
           setSelectedColumnIds([]);
           setSelectedRoofIds([]);
+          setSelectedContextObjectIds([]);
           setSelectedSectionLineId(null);
           switch (kind) {
             case "Wand":
@@ -3932,6 +3941,7 @@ export default function App() {
     sectionLine,
     selectedSectionLineId,
     selectedViewSnapshotId,
+    selectedContextObjectIds,
   ]);
 
   // ── Ausschnitt-Anwahl: „bleibt bis zur Abweichung" (DOSSIER A2) ───────────
@@ -4417,6 +4427,7 @@ export default function App() {
     setSelectedExtrudedSolidIds([]);
     setSelectedColumnIds([]);
     setSelectedRoofIds([]);
+    setSelectedContextObjectIds([]);
     setSelectedSectionLineId(null);
     setStampEditorRoomId(roomId);
   };
@@ -4433,6 +4444,7 @@ export default function App() {
     setSelectedExtrudedSolidIds([]);
     setSelectedColumnIds([]);
     setSelectedRoofIds([]);
+    setSelectedContextObjectIds([]);
     setSelectedSectionLineId(null);
     setEditTextId(drawingId);
   };
@@ -4546,6 +4558,7 @@ export default function App() {
       if (keep !== "extrudedSolid") setSelectedExtrudedSolidIds([]);
       if (keep !== "column") setSelectedColumnIds([]);
       if (keep !== "roof") setSelectedRoofIds([]);
+      setSelectedContextObjectIds([]);
       if (keep !== "sectionLine") setSelectedSectionLineId(null);
     };
     if (sel.sectionLineId) {
@@ -4596,6 +4609,7 @@ export default function App() {
     setSelectedExtrudedSolidIds([]);
     setSelectedColumnIds([]);
     setSelectedRoofIds([]);
+    setSelectedContextObjectIds([]);
     setSelectedSectionLineId(null);
   };
   // Rechts-Klick im Grundriss: Wand-Kontextmenü. Trifft der Klick eine Wand, die
@@ -4679,6 +4693,21 @@ export default function App() {
   // Leertreffer (kein Bauteil) → alle Selektionen leeren.
   const onViewport3dPick = (hit: Pick3dHit, additive: boolean) => {
     if (!hit) {
+      setSelectedWallIds([]);
+      setSelectedCeilingIds([]);
+      setSelectedDrawingId(null);
+      setSelectedOpeningIds([]);
+      setSelectedStairIds([]);
+      setSelectedRoomIds([]);
+      setSelectedExtrudedSolidIds([]);
+      setSelectedColumnIds([]);
+      setSelectedRoofIds([]);
+      setSelectedContextObjectIds([]);
+      setSelectedSectionLineId(null);
+      return;
+    }
+    if (hit.kind === "contextObject") {
+      setSelectedContextObjectIds([hit.id]);
       setSelectedWallIds([]);
       setSelectedCeilingIds([]);
       setSelectedDrawingId(null);
@@ -4704,6 +4733,7 @@ export default function App() {
       setSelectedExtrudedSolidIds([]);
       setSelectedColumnIds([]);
       setSelectedRoofIds([]);
+      setSelectedContextObjectIds([]);
       setSelectedSectionLineId(null);
       return;
     }
@@ -4717,6 +4747,7 @@ export default function App() {
       setSelectedExtrudedSolidIds([]);
       setSelectedColumnIds([]);
       setSelectedRoofIds([]);
+      setSelectedContextObjectIds([]);
       setSelectedSectionLineId(null);
       return;
     }
@@ -4730,6 +4761,7 @@ export default function App() {
       setSelectedRoomIds([]);
       setSelectedExtrudedSolidIds([]);
       setSelectedColumnIds([]);
+      setSelectedContextObjectIds([]);
       return;
     }
     if (hit.kind === "wall") {
@@ -4746,6 +4778,7 @@ export default function App() {
     setSelectedDrawingId(null);
     setSelectedOpeningIds([]);
     setSelectedStairIds([]);
+    setSelectedContextObjectIds([]);
     setSelectedRoomIds([]);
     setSelectedExtrudedSolidIds([]);
     setSelectedColumnIds([]);
@@ -5046,6 +5079,7 @@ export default function App() {
           selectedColumnIds={selectedColumnIds}
           selectedRoomIds={selectedRoomIds}
           selectedRoofIds={selectedRoofIds}
+          selectedContextObjectIds={selectedContextObjectIds}
           selectedSectionLineId={selectedSectionLineId}
           roomStamp={roomStamp}
           onStampMove={moveRoomStamp}
@@ -6185,6 +6219,7 @@ function Content({
   selectedColumnIds,
   selectedRoomIds,
   selectedRoofIds,
+  selectedContextObjectIds,
   selectedSectionLineId,
   roomStamp,
   onStampMove,
@@ -6265,6 +6300,7 @@ function Content({
   selectedColumnIds: string[];
   selectedRoomIds: string[];
   selectedRoofIds: string[];
+  selectedContextObjectIds: string[];
   selectedSectionLineId: string | null;
   roomStamp: { roomId: string; anchor: Vec2 } | null;
   onStampMove: (roomId: string, delta: Vec2) => void;
@@ -6337,7 +6373,8 @@ function Content({
       selectedCeilingIds.length === 0 &&
       selectedOpeningIds.length === 0 &&
       selectedStairIds.length === 0 &&
-      selectedRoofIds.length === 0
+      selectedRoofIds.length === 0 &&
+      selectedContextObjectIds.length === 0
         ? null
         : selectionHighlightLines(
             project,
@@ -6347,6 +6384,7 @@ function Content({
             selectedOpeningIds,
             selectedStairIds,
             selectedRoofIds,
+            selectedContextObjectIds,
           ),
     [
       project,
@@ -6355,6 +6393,7 @@ function Content({
       selectedOpeningIds,
       selectedStairIds,
       selectedRoofIds,
+      selectedContextObjectIds,
     ],
   );
 
diff --git a/src/panels/SitePanel.tsx b/src/panels/SitePanel.tsx
index 172e9da..27dc8ea 100644
--- a/src/panels/SitePanel.tsx
+++ b/src/panels/SitePanel.tsx
@@ -115,7 +115,13 @@ export function SitePanel() {
       ) : (
         <ul className="site-list">
           {objects.map((obj) => (
-            <li key={obj.id} className="site-row">
+            <li
+              key={obj.id}
+              className={
+                "site-row" +
+                (host.selectedContextObjectIds.includes(obj.id) ? " site-row-selected" : "")
+              }
+            >
               <span className="site-name" title={obj.name}>
                 {obj.name}
               </span>
diff --git a/src/panels/host.ts b/src/panels/host.ts
index 806e682..9595155 100644
--- a/src/panels/host.ts
+++ b/src/panels/host.ts
@@ -402,6 +402,8 @@ export interface PanelHostValue {
   // ── Site-/Kontext-Schicht (SitePanel) ───────────────────────────────────
   /** Aktuelle Kontext-Objekte (Meshes/Konturen/Gelände) aus `project.context`. */
   contextObjects: ContextObject[];
+  /** Im 3D-Viewport angewählte Kontext-Objekte (Umriss-Hervorhebung), s. selectionSlice. */
+  selectedContextObjectIds: string[];
   /** Fügt mehrere Kontext-Objekte hinzu (z. B. aus einem DXF-Import). */
   onAddContextObjects: (objs: ContextObject[]) => void;
   /** Entfernt ein Kontext-Objekt per ID. */
diff --git a/src/plan/toWalls3d.test.ts b/src/plan/toWalls3d.test.ts
index 314a125..d5051c3 100644
--- a/src/plan/toWalls3d.test.ts
+++ b/src/plan/toWalls3d.test.ts
@@ -101,6 +101,48 @@ describe("selectionHighlightLines", () => {
   });
 });
 
+describe("selectionHighlightLines — Kontext-Objekte", () => {
+  // Ein einzelnes Dreieck als Kontext-Mesh (importiertes Gebäude): das
+  // Highlight zeichnet dessen achsenparallele Bounding-Box (12 Kanten), NICHT
+  // das volle Dreiecks-Wireframe (s. Kommentar in toWalls3d.ts).
+  const withContext: Project = {
+    ...sampleProject,
+    context: [
+      {
+        id: "CTX1",
+        type: "importedMesh",
+        name: "Testgebäude",
+        positions: [0, 0, 0, 2, 0, 0, 2, 3, 4],
+        indices: [0, 1, 2],
+      },
+    ],
+  };
+
+  it("leere Kontext-Auswahl -> leeres Array", () => {
+    const lines = selectionHighlightLines(withContext, [], [], RGB, [], [], [], []);
+    expect(lines.length).toBe(0);
+  });
+
+  it("unbekannte Kontext-Id -> leeres Array", () => {
+    const lines = selectionHighlightLines(withContext, [], [], RGB, [], [], [], ["does-not-exist"]);
+    expect(lines.length).toBe(0);
+  });
+
+  it("ein Kontext-Objekt -> Bounding-Box-Umriss (12 Kanten)", () => {
+    const lines = selectionHighlightLines(withContext, [], [], RGB, [], [], [], ["CTX1"]);
+    expect(lines.length).toBe(12 * VERTICES_PER_EDGE * FLOATS_PER_VERTEX);
+    expect(lines[3]).toBeCloseTo(RGB[0], 6);
+    expect(lines[5]).toBeCloseTo(RGB[2], 6);
+  });
+
+  it("Kontext-Objekt zusammen mit einer Wand -> Summe der Einzelgeometrien", () => {
+    const wallOnly = selectionHighlightLines(withContext, ["W2"], [], RGB);
+    const ctxOnly = selectionHighlightLines(withContext, [], [], RGB, [], [], [], ["CTX1"]);
+    const both = selectionHighlightLines(withContext, ["W2"], [], RGB, [], [], [], ["CTX1"]);
+    expect(both.length).toBe(wallOnly.length + ctxOnly.length);
+  });
+});
+
 describe("Öffnungen als echte Löcher in EINEM Körper (3D-Pfad, layeredWalls:true)", () => {
   // Wand W1 (EG, Wandtyp "aw" = 4 Schichten) mit ZWEI Fenstern, deren Achsen-
   // Intervalle sich ÜBERLAPPEN, aber auf UNTERSCHIEDLICHER Höhe liegen:
@@ -1890,3 +1932,52 @@ describe("pickGeometry — Dächer (Ray-Dreieck-Pick)", () => {
     for (const tri of roofs[0].tris) for (const p of tri) expect(p[1]).toBeGreaterThan(0);
   });
 });
+
+describe("pickGeometry — Kontext-Meshes (importierte Gebäude/Terrain)", () => {
+  const withContext: Project = {
+    ...sampleProject,
+    context: [
+      {
+        id: "CTX1",
+        type: "importedMesh",
+        name: "Testgebäude",
+        // model (x,y,z=Höhe) -> world (x, z, y): ein Dreieck.
+        positions: [0, 0, 0, 2, 0, 0, 2, 3, 4],
+        indices: [0, 1, 2],
+      },
+      {
+        id: "CONTOURS1",
+        type: "contourSet",
+        name: "Höhenlinien",
+        contours: [],
+      },
+    ],
+  };
+
+  it("liefert je Kontext-Objekt World-Dreiecke, contourSet wird übersprungen", () => {
+    const { contextMeshes } = pickGeometry(withContext);
+    expect(contextMeshes.length).toBe(1);
+    expect(contextMeshes[0].contextObjectId).toBe("CTX1");
+    expect(contextMeshes[0].tris.length).toBe(1);
+    // world = (x, z, y) — dasselbe Dreieck (0,0,0),(2,0,0),(2,3,4)
+    // -> world (0,0,0),(2,0,0),(2,4,3).
+    expect(contextMeshes[0].tris[0][2]).toEqual([2, 4, 3]);
+  });
+
+  it("kaputte Indizes werden robust übersprungen statt abzustürzen", () => {
+    const broken: Project = {
+      ...sampleProject,
+      context: [
+        {
+          id: "CTX2",
+          type: "importedMesh",
+          name: "Kaputt",
+          positions: [0, 0, 0, 1, 0, 0, 1, 1, 0],
+          indices: [0, 1, 99], // Index 99 existiert nicht
+        },
+      ],
+    };
+    const { contextMeshes } = pickGeometry(broken);
+    expect(contextMeshes.length).toBe(0);
+  });
+});
diff --git a/src/plan/toWalls3d.ts b/src/plan/toWalls3d.ts
index df27fdb..b335dfb 100644
--- a/src/plan/toWalls3d.ts
+++ b/src/plan/toWalls3d.ts
@@ -62,7 +62,7 @@ import type { WallCuts } from "../model/joins";
 import { add, dot, leftNormal, lineIntersect, normalize, scale, sub } from "../model/geometry";
 import type { Line } from "../model/geometry";
 import { resolveHatch } from "./generatePlan";
-import type { PickOpening, PickRoof, PickStair } from "../viewport/raycast3d";
+import type { PickOpening, PickRoof, PickStair, PickContextMesh } from "../viewport/raycast3d";
 
 /** World-Punkt [x, Höhe, y] für den Dach-Pick (Vec3-Konvention von raycast3d). */
 type RoofPickVec3 = [number, number, number];
@@ -2825,6 +2825,7 @@ export function pickGeometry(
   openings: PickOpening[];
   stairs: PickStair[];
   roofs: PickRoof[];
+  contextMeshes: PickContextMesh[];
 } {
   // Dächer: Dachflächen + Giebel als WORLD-Dreiecke (fan-trianguliert wie
   // emitRoofs; model [x,y,z=Höhe] → world [x, z, y]) — präzise geneigte
@@ -2878,7 +2879,27 @@ export function pickGeometry(
       stairId: st.id,
     });
   }
-  return { walls: projectToWalls3d(project), slabs: emitSlabs(project), openings, stairs, roofs };
+  // Kontext-Meshes (importierte Gebäude/Terrain, s. ContextObject): rohe
+  // WORLD-Dreiecke wie beim Dach, direkt aus dem Indexpuffer (kein Fan nötig —
+  // ImportedMesh/TerrainMesh liefern bereits ein echtes Dreiecksnetz). Kaputte
+  // Indizes robust überspringen statt abzustürzen (importierte Daten).
+  const contextMeshes: PickContextMesh[] = [];
+  for (const obj of project.context ?? []) {
+    if (obj.type === "contourSet") continue;
+    const pos = obj.positions;
+    const vcount = pos.length / 3;
+    const tris: [RoofPickVec3, RoofPickVec3, RoofPickVec3][] = [];
+    for (let i = 0; i + 2 < obj.indices.length; i += 3) {
+      const ia = obj.indices[i];
+      const ib = obj.indices[i + 1];
+      const ic = obj.indices[i + 2];
+      if (ia >= vcount || ib >= vcount || ic >= vcount) continue;
+      const at = (idx: number): RoofPickVec3 => [pos[idx * 3], pos[idx * 3 + 2], pos[idx * 3 + 1]];
+      tris.push([at(ia), at(ib), at(ic)]);
+    }
+    if (tris.length > 0) contextMeshes.push({ tris, contextObjectId: obj.id });
+  }
+  return { walls: projectToWalls3d(project), slabs: emitSlabs(project), openings, stairs, roofs, contextMeshes };
 }
 
 /**
@@ -2915,13 +2936,15 @@ export function selectionHighlightLines(
   openingIds: string[] = [],
   stairIds: string[] = [],
   roofIds: string[] = [],
+  contextObjectIds: string[] = [],
 ): Float32Array {
   if (
     wallIds.length === 0 &&
     ceilingIds.length === 0 &&
     openingIds.length === 0 &&
     stairIds.length === 0 &&
-    roofIds.length === 0
+    roofIds.length === 0 &&
+    contextObjectIds.length === 0
   ) {
     return new Float32Array(0);
   }
@@ -2931,6 +2954,7 @@ export function selectionHighlightLines(
   const openingSet = new Set(openingIds);
   const stairSet = new Set(stairIds);
   const roofSet = new Set(roofIds);
+  const contextObjSet = new Set(contextObjectIds);
   const out: number[] = [];
   const pushEdge = (a: RVec3, b: RVec3) => {
     out.push(a[0], a[1], a[2], rgb[0], rgb[1], rgb[2]);
@@ -3013,5 +3037,35 @@ export function selectionHighlightLines(
       for (const gab of g.gables) polyEdges(gab);
     }
   }
+  // Kontext-Objekt (importiertes Gebäude/Terrain): Umriss als achsenparallele
+  // Bounding-Box statt vollem Dreiecks-Wireframe — importierte Meshes haben oft
+  // tausende Dreiecke, deren Kanten einzeln zu zeichnen wäre unbrauchbar dicht.
+  if (contextObjSet.size > 0) {
+    for (const obj of project.context ?? []) {
+      if (obj.type === "contourSet" || !contextObjSet.has(obj.id)) continue;
+      const pos = obj.positions;
+      let minX = Infinity, maxX = -Infinity;
+      let minY = Infinity, maxY = -Infinity;
+      let minH = Infinity, maxH = -Infinity;
+      for (let i = 0; i + 2 < pos.length; i += 3) {
+        const x = pos[i], y = pos[i + 1], h = pos[i + 2];
+        if (x < minX) minX = x;
+        if (x > maxX) maxX = x;
+        if (y < minY) minY = y;
+        if (y > maxY) maxY = y;
+        if (h < minH) minH = h;
+        if (h > maxH) maxH = h;
+      }
+      if (!isFinite(minX)) continue;
+      const corners: RVec3[] = [];
+      for (let i = 0; i < 8; i++) {
+        const x = i & 1 ? maxX : minX;
+        const h = i & 2 ? maxH : minH;
+        const y = i & 4 ? maxY : minY;
+        corners.push([x, h, y]);
+      }
+      for (const [i, j] of BOX_EDGES) pushEdge(corners[i], corners[j]);
+    }
+  }
   return new Float32Array(out);
 }
diff --git a/src/state/selectionSlice.ts b/src/state/selectionSlice.ts
index 3da70a9..194fb36 100644
--- a/src/state/selectionSlice.ts
+++ b/src/state/selectionSlice.ts
@@ -25,6 +25,8 @@ export interface SelectionSlice {
   selectedColumnIds: string[];
   // Gewählte Dächer als MENGE von IDs — getrennt von den übrigen Kanälen.
   selectedRoofIds: string[];
+  // Gewählte Kontext-Objekte (importierte Gebäude/Terrain) als MENGE von IDs.
+  selectedContextObjectIds: string[];
   // Gewählte Schnitt-/Ansichtslinie (DrawingLevel-Id) — EINZELauswahl (eine Linie
   // zur Zeit), getrennt von den übrigen Kanälen. `null` = keine Linie gewählt.
   selectedSectionLineId: string | null;
@@ -38,6 +40,7 @@ export interface SelectionSlice {
   setSelectedExtrudedSolidIds: (ids: string[]) => void;
   setSelectedColumnIds: (ids: string[]) => void;
   setSelectedRoofIds: (ids: string[]) => void;
+  setSelectedContextObjectIds: (ids: string[]) => void;
   setSelectedSectionLineId: (id: string | null) => void;
   /** Auswahl (Wände + Decken + Öffnungen + Treppen + Dächer + 2D-Elemente) leeren. */
   clearSelection: () => void;
@@ -57,6 +60,7 @@ export function createSelectionSlice(
     selectedExtrudedSolidIds: [],
     selectedColumnIds: [],
     selectedRoofIds: [],
+    selectedContextObjectIds: [],
     selectedSectionLineId: null,
     setSelectedWallIds: (ids) => set({ selectedWallIds: ids }),
     setSelectedDrawingIds: (ids) => set({ selectedDrawingIds: ids }),
@@ -67,6 +71,7 @@ export function createSelectionSlice(
     setSelectedExtrudedSolidIds: (ids) => set({ selectedExtrudedSolidIds: ids }),
     setSelectedColumnIds: (ids) => set({ selectedColumnIds: ids }),
     setSelectedRoofIds: (ids) => set({ selectedRoofIds: ids }),
+    setSelectedContextObjectIds: (ids) => set({ selectedContextObjectIds: ids }),
     setSelectedSectionLineId: (id) => set({ selectedSectionLineId: id }),
     clearSelection: () =>
       set({
@@ -79,6 +84,7 @@ export function createSelectionSlice(
         selectedExtrudedSolidIds: [],
         selectedColumnIds: [],
         selectedRoofIds: [],
+        selectedContextObjectIds: [],
         selectedSectionLineId: null,
       }),
   };
diff --git a/src/styles.css b/src/styles.css
index bb88601..71d01dd 100644
--- a/src/styles.css
+++ b/src/styles.css
@@ -4043,6 +4043,10 @@ body {
 .site-panel .site-row:hover {
   background: var(--accent-dim);
 }
+.site-panel .site-row-selected {
+  background: var(--accent-dim);
+  outline: 1px solid var(--accent);
+}
 .site-panel .site-name {
   flex: 1 1 auto;
   min-width: 0;
diff --git a/src/viewport/Wasm3DViewport.tsx b/src/viewport/Wasm3DViewport.tsx
index be0bbb5..e6f9432 100644
--- a/src/viewport/Wasm3DViewport.tsx
+++ b/src/viewport/Wasm3DViewport.tsx
@@ -57,7 +57,7 @@ import { drawingGripVertices, drawingMoveAnchor } from "./drawingGrips";
 
 /** Ein per 3D-Klick getroffenes Bauteil, oder null (Leerraum). */
 export type Pick3dHit =
-  | { kind: "wall" | "ceiling" | "opening" | "stair" | "roof"; id: string }
+  | { kind: "wall" | "ceiling" | "opening" | "stair" | "roof" | "contextObject"; id: string }
   | null;
 
 /** Klick-vs-Drag-Schwelle (Pixel): bleibt die Maus zwischen pointerdown und
@@ -798,10 +798,10 @@ export function Wasm3DViewport({
       const ndc = toNdc(clientX, clientY);
       if (!cb || !o || !ndc) return;
       const ray = cameraRay(orbitCamera(o), ndc.ndcX, ndc.ndcY, ndc.aspect);
-      const { walls, slabs, openings, stairs, roofs } = pickGeometry(projectRef.current);
-      // Erweiterter Pick inkl. Öffnungen (Fenster/Türen) + Treppen — sonst wären
-      // im WASM-Viewport nur Wände/Decken anwählbar.
-      const hit = pickNearest(ray, walls, slabs, openings, stairs, roofs);
+      const { walls, slabs, openings, stairs, roofs, contextMeshes } = pickGeometry(projectRef.current);
+      // Erweiterter Pick inkl. Öffnungen (Fenster/Türen) + Treppen + Kontext-
+      // Meshes — sonst wären im WASM-Viewport nur Wände/Decken anwählbar.
+      const hit = pickNearest(ray, walls, slabs, openings, stairs, roofs, contextMeshes);
       cb(hit ? { kind: hit.kind, id: hit.id } : null, additive);
     };
 
diff --git a/src/viewport/raycast3d.test.ts b/src/viewport/raycast3d.test.ts
index c173393..9091d69 100644
--- a/src/viewport/raycast3d.test.ts
+++ b/src/viewport/raycast3d.test.ts
@@ -9,6 +9,7 @@ import {
   type PickSlab,
   type PickOpening,
   type PickStair,
+  type PickContextMesh,
 } from "./raycast3d";
 
 // Kamera bei (0,1,10), Blick entlang -Z auf (0,1,0). Zentraler Strahl (ndc 0,0)
@@ -207,3 +208,69 @@ describe("pickNearest — Öffnungen und Treppen", () => {
     expect(hit!.id).toBe("w1");
   });
 });
+
+// Kontext-Mesh (importiertes Gebäude/Terrain): eine flache, senkrechte
+// Rechteckfläche bei model y=5 (world z=5), model x∈[-1,1], model z (Höhe)
+// ∈[0,2] — dieselbe Front wie WALL, aber als rohes Dreiecksnetz statt Quader.
+const CONTEXT_MESH: PickContextMesh = {
+  tris: [
+    [
+      [-1, 0, 5],
+      [1, 0, 5],
+      [1, 2, 5],
+    ],
+    [
+      [-1, 0, 5],
+      [1, 2, 5],
+      [-1, 2, 5],
+    ],
+  ],
+  contextObjectId: "ctx1",
+};
+
+describe("pickNearest — Kontext-Meshes", () => {
+  it("Strahl auf ein Kontext-Mesh liefert contextObjectId", () => {
+    const hit = pickNearest(
+      { origin: [0, 1, 10], dir: [0, 0, -1] },
+      [],
+      [],
+      [],
+      [],
+      [],
+      [CONTEXT_MESH],
+    );
+    expect(hit).not.toBeNull();
+    expect(hit!.kind).toBe("contextObject");
+    expect(hit!.contextObjectId).toBe("ctx1");
+    expect(hit!.t).toBeCloseTo(5, 6);
+  });
+
+  it("Strahl neben dem Mesh verfehlt", () => {
+    const hit = pickNearest(
+      { origin: [5, 1, 10], dir: [0, 0, -1] },
+      [],
+      [],
+      [],
+      [],
+      [],
+      [CONTEXT_MESH],
+    );
+    expect(hit).toBeNull();
+  });
+
+  it("bei näherer Wand gewinnt die Wand vor dem weiter entfernten Kontext-Mesh", () => {
+    // WALL-Front bei z=5.1 → t=4.9, näher als das Mesh bei z=5 (t=5).
+    const hit = pickNearest(
+      { origin: [0, 1, 10], dir: [0, 0, -1] },
+      [WALL],
+      [],
+      [],
+      [],
+      [],
+      [CONTEXT_MESH],
+    );
+    expect(hit).not.toBeNull();
+    expect(hit!.kind).toBe("wall");
+    expect(hit!.id).toBe("w1");
+  });
+});
diff --git a/src/viewport/raycast3d.ts b/src/viewport/raycast3d.ts
index eb39a9d..035c86b 100644
--- a/src/viewport/raycast3d.ts
+++ b/src/viewport/raycast3d.ts
@@ -96,15 +96,29 @@ export interface PickRoof {
   roofId: string;
 }
 
+/**
+ * Minimal-Form eines Kontext-Meshes (importiertes Gebäude/Terrain, s.
+ * `ContextObject`) für den Raycast: rohe WORLD-Dreiecke (dieselbe Konvention
+ * wie {@link PickRoof} — model (x,y,z=Höhe) → world (x, z, y)), keine
+ * Vereinfachung auf ein Bounding-Prisma (Gebäude-Meshes sind zu unregelmässig
+ * dafür, ein grosszügiges Prisma stähle Klicks auf dahinterliegende Bauteile).
+ */
+export interface PickContextMesh {
+  tris: ReadonlyArray<readonly [Vec3, Vec3, Vec3]>;
+  contextObjectId: string;
+}
+
 /** Ergebnis eines Picks: getroffenes Bauteil + Distanz entlang des Strahls. */
 export interface PickHit {
-  kind: "wall" | "ceiling" | "opening" | "stair" | "roof";
+  kind: "wall" | "ceiling" | "opening" | "stair" | "roof" | "contextObject";
   id: string;
   t: number;
   /** Bei `kind:"opening"` dieselbe Id wie `id` (ausdrucksstärkerer Zugriff). */
   openingId?: string;
   /** Bei `kind:"stair"` dieselbe Id wie `id` (ausdrucksstärkerer Zugriff). */
   stairId?: string;
+  /** Bei `kind:"contextObject"` dieselbe Id wie `id` (ausdrucksstärkerer Zugriff). */
+  contextObjectId?: string;
 }
 
 const EPS = 1e-9;
@@ -362,6 +376,17 @@ function rayRoofTris(ray: Ray, roof: PickRoof): number | null {
   return best;
 }
 
+/** Kleinstes t über alle Dreiecke eines Kontext-Meshes, oder null — wie
+ *  {@link rayRoofTris}, dieselbe doppelseitige {@link rayTriangle}. */
+function rayContextMeshTris(ray: Ray, mesh: PickContextMesh): number | null {
+  let best: number | null = null;
+  for (const [a, b, c] of mesh.tris) {
+    const t = rayTriangle(ray, a, b, c);
+    if (t !== null && (best === null || t < best)) best = t;
+  }
+  return best;
+}
+
 // Overload OHNE Öffnungen/Treppen: bleibt exakt die bisherige Signatur, sodass
 // der bestehende Aufrufer (Wasm3DViewport.tsx: `pickNearest(ray, walls, slabs)`)
 // unverändert kompiliert — inklusive des dort erwarteten engen `kind`-Typs
@@ -372,7 +397,8 @@ export function pickNearest(
   walls: readonly PickWall[],
   slabs: readonly PickSlab[],
 ): (PickHit & { kind: "wall" | "ceiling" }) | null;
-// Erweiterter Overload MIT Öffnungen/Treppen/Dächern: `kind` deckt alle Arten ab.
+// Erweiterter Overload MIT Öffnungen/Treppen/Dächern/Kontext-Meshes: `kind`
+// deckt alle Arten ab.
 export function pickNearest(
   ray: Ray,
   walls: readonly PickWall[],
@@ -380,6 +406,7 @@ export function pickNearest(
   openings: readonly PickOpening[],
   stairs?: readonly PickStair[],
   roofs?: readonly PickRoof[],
+  contextMeshes?: readonly PickContextMesh[],
 ): PickHit | null;
 /**
  * Nächstes getroffenes Bauteil (kleinstes t) über Wände, Decken, Öffnungen und
@@ -397,6 +424,7 @@ export function pickNearest(
   openings: readonly PickOpening[] = [],
   stairs: readonly PickStair[] = [],
   roofs: readonly PickRoof[] = [],
+  contextMeshes: readonly PickContextMesh[] = [],
 ): PickHit | null {
   const TIE_EPS = 1e-6;
   let hit: PickHit | null = null;
@@ -433,6 +461,13 @@ export function pickNearest(
     const t = rayRoofTris(ray, r);
     if (t !== null) consider({ kind: "roof", id: r.roofId, t }, 1);
   }
+  // Kontext-Meshes (importierte Gebäude/Terrain): Rang wie Wand/Decke/Dach.
+  for (const m of contextMeshes) {
+    const t = rayContextMeshTris(ray, m);
+    if (t !== null) {
+      consider({ kind: "contextObject", id: m.contextObjectId, t, contextObjectId: m.contextObjectId }, 1);
+    }
+  }
   return hit;
 }