diff --git a/src/components/three/ModelViewer.tsx b/src/components/three/ModelViewer.tsx
index dd1f5ad..af51442 100644
--- a/src/components/three/ModelViewer.tsx
+++ b/src/components/three/ModelViewer.tsx
@@ -459,61 +459,93 @@ function HoverDetector() {
   return null;
 }
 
-/** Raycasting click handler for measurement mode – uses snap point when available */
+/** Pointer handler for measurement mode – uses snap point when available.
+ *  Uses pointerdown/up with a drag gate so accidental drags don't add points. */
 function MeasureClickHandler() {
   const { camera, scene, gl } = useThree();
   const measureMode = useModelStore((s) => s.measureMode);
-  const addMeasurePoint = useModelStore((s) => s.addMeasurePoint);
-  const snapPoint = useModelStore((s) => s.snapPoint);
   const raycaster = useMemo(() => new THREE.Raycaster(), []);
   const mouse = useMemo(() => new THREE.Vector2(), []);
 
-  const handleClick = useCallback((event: MouseEvent) => {
-    if (!measureMode) return;
-
-    // Use snap point if available
-    if (snapPoint) {
-      addMeasurePoint({ x: snapPoint.x, y: snapPoint.y, z: snapPoint.z });
+  useEffect(() => {
+    if (!measureMode) {
+      gl.domElement.style.cursor = 'grab';
       return;
     }
+    gl.domElement.style.cursor = 'crosshair';
 
-    const rect = gl.domElement.getBoundingClientRect();
-    mouse.x = ((event.clientX - rect.left) / rect.width) * 2 - 1;
-    mouse.y = -((event.clientY - rect.top) / rect.height) * 2 + 1;
+    const canvas = gl.domElement;
+    let downX = 0, downY = 0, downBtn = 0;
+    let armed = false;
 
-    raycaster.setFromCamera(mouse, camera);
-    const intersects = raycaster.intersectObjects(scene.children, true);
+    const onDown = (e: PointerEvent) => {
+      if (e.button !== 0) { armed = false; return; }
+      downX = e.clientX;
+      downY = e.clientY;
+      downBtn = e.button;
+      armed = true;
+    };
 
-    const hit = intersects.find(i => {
-      const obj = i.object;
-      if (obj instanceof THREE.GridHelper) return false;
-      if (obj instanceof THREE.Mesh) {
+    const onUp = (e: PointerEvent) => {
+      if (!armed || e.button !== downBtn) return;
+      armed = false;
+      const dx = e.clientX - downX;
+      const dy = e.clientY - downY;
+      if (Math.hypot(dx, dy) > 4) return; // it was a drag, not a click
+
+      const st = useModelStore.getState();
+      if (!st.measureMode) return;
+
+      // Prefer snap
+      if (st.snapPoint) {
+        st.addMeasurePoint({ x: st.snapPoint.x, y: st.snapPoint.y, z: st.snapPoint.z });
+        return;
+      }
+
+      const rect = canvas.getBoundingClientRect();
+      mouse.x = ((e.clientX - rect.left) / rect.width) * 2 - 1;
+      mouse.y = -((e.clientY - rect.top) / rect.height) * 2 + 1;
+      raycaster.setFromCamera(mouse, camera);
+      const intersects = raycaster.intersectObjects(scene.children, true);
+      const hit = intersects.find(i => {
+        const obj = i.object;
+        if (!(obj instanceof THREE.Mesh)) return false;
+        if (obj.userData.__edgeLine) return false;
         if (obj.geometry instanceof THREE.SphereGeometry) return false;
         if (obj.geometry instanceof THREE.RingGeometry) return false;
+        if (obj.geometry instanceof THREE.PlaneGeometry) return false;
+        return true;
+      });
+      if (hit) {
+        st.addMeasurePoint({ x: hit.point.x, y: hit.point.y, z: hit.point.z });
       }
-      return true;
-    });
+    };
 
-    if (hit) {
-      addMeasurePoint({ x: hit.point.x, y: hit.point.y, z: hit.point.z });
-    }
-  }, [measureMode, addMeasurePoint, snapPoint, camera, scene, gl, raycaster, mouse]);
+    const onKey = (e: KeyboardEvent) => {
+      const st = useModelStore.getState();
+      if (!st.measureMode) return;
+      if (e.key === 'Escape') {
+        if (st.measurePoints.length > 0) st.undoLastMeasurePoint();
+      } else if ((e.key === 'z' || e.key === 'Z') && !e.ctrlKey && !e.metaKey) {
+        st.undoLastMeasurement();
+      }
+    };
 
-  useEffect(() => {
-    const canvas = gl.domElement;
-    canvas.addEventListener('click', handleClick);
-    return () => canvas.removeEventListener('click', handleClick);
-  }, [gl, handleClick]);
-
-  // Change cursor when in measure mode
-  useEffect(() => {
-    gl.domElement.style.cursor = measureMode ? 'crosshair' : 'grab';
-    return () => { gl.domElement.style.cursor = 'grab'; };
-  }, [measureMode, gl]);
+    canvas.addEventListener('pointerdown', onDown);
+    canvas.addEventListener('pointerup', onUp);
+    window.addEventListener('keydown', onKey);
+    return () => {
+      canvas.removeEventListener('pointerdown', onDown);
+      canvas.removeEventListener('pointerup', onUp);
+      window.removeEventListener('keydown', onKey);
+      gl.domElement.style.cursor = 'grab';
+    };
+  }, [measureMode, camera, scene, gl, raycaster, mouse]);
 
   return null;
 }
 
+
 function GridLayer() {
   const showGrid = useModelStore((s) => s.showGrid);
   const gridY = useModelStore((s) => s.gridY);