diff --git a/PVPlantPlacement.py b/PVPlantPlacement.py
index 3203ec4..011d92f 100644
--- a/PVPlantPlacement.py
+++ b/PVPlantPlacement.py
@@ -1186,6 +1186,8 @@ class _PVPlantPlacementTaskPanel:
         self.Dir = FreeCAD.Vector(0, -1, 0)
         self._terrain_interpolator = None
         self._frame_footprints_cache = {}
+        self._isinside_cache = {}  # LRU: (frame_name, x, y) -> bool
+        self._area_polygon = None  # Caché shapely del área
 
         # UI setup
         self.form = FreeCADGui.PySideUic.loadUi(os.path.join(PVPlantResources.__dir__, "PVPlantPlacement.ui"))
@@ -1285,8 +1287,10 @@ class _PVPlantPlacementTaskPanel:
             if prohibited_faces:
                 self.Area = self.Area.cut(prohibited_faces)
 
-        # Clear terrain interpolator cache when area changes
+        # Clear caches when area changes
         self._terrain_interpolator = None
+        self._area_polygon = None
+        self._isinside_cache.clear()
 
     def _setup_terrain_interpolator(self):
         """Cached terrain interpolator"""
@@ -1425,18 +1429,53 @@ class _PVPlantPlacementTaskPanel:
 
         return df
 
+    def _get_area_polygon(self):
+        """Convierte self.Area a shapely Polygon para comprobaciones rápidas"""
+        if self._area_polygon is None and self.Area:
+            from shapely.geometry import Polygon
+            verts = self.Area.Vertexes
+            if len(verts) >= 3:
+                self._area_polygon = Polygon([(v.x, v.y) for v in verts])
+        return self._area_polygon
+
     def isInside(self, frame, point):
-        """Optimized inside check with early termination"""
-        if not self.Area.isInside(point, 1e-6, True):  # Reduced tolerance for speed
+        """
+        Comprueba si un frame cabe en el área en un punto dado.
+        Usa shapely para la comprobación 2D (mucho más rápido que Part.cut).
+        """
+        # Caché LRU: mismo frame + misma posición
+        key = (frame.Name, round(point.x, 0), round(point.y, 0))
+        if key in self._isinside_cache:
+            return self._isinside_cache[key]
+
+        # Prefiltro rápido por BoundBox
+        fw, fl = frame.Width.Value / 2, frame.Length.Value / 2
+        if (point.x - fw < self.Area.BoundBox.XMin or
+            point.x + fw > self.Area.BoundBox.XMax or
+            point.y - fl < self.Area.BoundBox.YMin or
+            point.y + fl > self.Area.BoundBox.YMax):
+            self._isinside_cache[key] = False
             return False
 
-        frame_footprint = self._get_frame_footprint(frame)
-        frame_footprint.Placement.Base = point
+        # Comprobación precisa con shapely
+        ap = self._get_area_polygon()
+        if ap is not None:
+            from shapely.geometry import box
+            fp = box(point.x - fw, point.y - fl, point.x + fw, point.y + fl)
+            result = ap.contains(fp)
+            self._isinside_cache[key] = result
+            return result
 
+        # Fallback OCC (si shapely falla)
         try:
+            frame_footprint = self._get_frame_footprint(frame)
+            frame_footprint.Placement.Base = point
             cut = frame_footprint.cut([self.Area])
-            return len(cut.Vertexes) == 0
-        except:
+            result = len(cut.Vertexes) == 0
+            self._isinside_cache[key] = result
+            return result
+        except Part.OCCError:
+            self._isinside_cache[key] = False
             return False
 
     def getAligments(self):