Changes

Co-authored-by: Reifonas <211114984+Reifonas@users.noreply.github.com>

src/components/three/ModelViewer.tsx

@@ -1078,6 +1078,43 @@ function GridAutoFollower() {
   return null;
 }
 
+/** When gridCalibMode is on, the next click on the model sets the grid Y to
+ *  the world Y of the clicked surface point and disables auto-follow. */
+function GridCalibrationHandler() {
+  const { camera, scene, gl } = useThree();
+  const gridCalibMode = useModelStore((s) => s.gridCalibMode);
+  const raycaster = useMemo(() => new THREE.Raycaster(), []);
+  const mouse = useMemo(() => new THREE.Vector2(), []);
+  useEffect(() => {
+    if (!gridCalibMode) return;
+    const canvas = gl.domElement;
+    const prevCursor = canvas.style.cursor;
+    canvas.style.cursor = 'crosshair';
+    const onPointerUp = (ev: PointerEvent) => {
+      if (ev.button !== 0) return;
+      const rect = canvas.getBoundingClientRect();
+      mouse.x = ((ev.clientX - rect.left) / rect.width) * 2 - 1;
+      mouse.y = -((ev.clientY - rect.top) / rect.height) * 2 + 1;
+      raycaster.setFromCamera(mouse, camera);
+      const hits = raycaster.intersectObjects(scene.children, true);
+      const hit = hits.find((h) => isPickableModelMesh(h.object));
+      if (!hit) return;
+      useModelStore.setState({
+        gridY: hit.point.y - 0.001,
+        gridAutoFollow: false,
+        gridCalibMode: false,
+        showGrid: true,
+      });
+    };
+    canvas.addEventListener('pointerup', onPointerUp);
+    return () => {
+      canvas.removeEventListener('pointerup', onPointerUp);
+      canvas.style.cursor = prevCursor;
+    };
+  }, [gridCalibMode, camera, scene, gl, raycaster, mouse]);
+  return null;
+}
+
 /** Mouse drag handler for desktop "Posicionar" mode: translates/rotates the active model. */
 function PositionDragHandler() {
   const { camera, gl, scene } = useThree();