diff --git a/public/boardViewer.html b/public/boardViewer.html
index df3864e..491bb09 100644
--- a/public/boardViewer.html
+++ b/public/boardViewer.html
@@ -366,6 +366,11 @@ function buildSkeletonFK(robot, angles) {
         const corner0W   = posWorld.clone().add(ptrDir.multiplyScalar(markerSizeM * Math.SQRT1_2));
         gArmMarkers.add(makeLine(posWorld, corner0W, col, 0.9));
         gArmMarkers.add(makeSphere(corner0W, 0.0008, col));
+
+        // Modell-Normale (Pfeil, gleiche Link-Farbe, halbtransparent)
+        const modelNormalEnd = posWorld.clone().add(normalW.clone().multiplyScalar(markerSizeM * 1.5));
+        gArmMarkers.add(makeLine(posWorld, modelNormalEnd, col, 0.5));
+        gArmMarkers.add(makeSphere(modelNormalEnd, 0.0005, col));
       }
     }
   }
@@ -391,8 +396,28 @@ function buildSkeletonFK(robot, angles) {
       const [lx, ly, lz] = modelM.position;
       const modelPosW = new THREE.Vector3(lx * S, lz * S, -ly * S).applyMatrix4(frames[obsLink]);
       const obsPosW   = r2vArr(obs.position_mm);
+      const obsCol    = LINK_COLORS[obsLink] ?? 0x3b82f6;
       gArmMarkers.add(makeLine(modelPosW, obsPosW, 0xff8800, 0.85));
-      gArmMarkers.add(makeSphere(obsPosW, 0.007, LINK_COLORS[obsLink] ?? 0x3b82f6));
+      gArmMarkers.add(makeSphere(obsPosW, 0.007, obsCol));
+
+      // Beobachtungs-Ecke 0: Orientierungszeiger für Spin-Vergleich
+      // corners_m sind Weltkoordinaten in Metern → direkt in Three.js (Y↑=Z, Z↑=-Y)
+      const c0 = obs.corners_m?.[0];
+      if (c0) {
+        const obsCorner0W = new THREE.Vector3(c0[0], c0[2], -c0[1]);
+        gArmMarkers.add(makeLine(obsPosW, obsCorner0W, obsCol, 0.85));
+        gArmMarkers.add(makeSphere(obsCorner0W, 0.006, obsCol));
+      }
+
+      // Beobachtungs-Normale (weißer Pfeil)
+      if (obs.normal) {
+        const [on0, on1, on2] = obs.normal;
+        const obsNormalW   = new THREE.Vector3(on0, on2, -on1).normalize();
+        const arrowLen     = (modelM.size ?? 25) * S * 1.5;
+        const obsNormalEnd = obsPosW.clone().add(obsNormalW.multiplyScalar(arrowLen));
+        gArmMarkers.add(makeLine(obsPosW, obsNormalEnd, 0xffffff, 0.55));
+        gArmMarkers.add(makeSphere(obsNormalEnd, 0.005, 0xffffff));
+      }
     }
   }
 }