x

src/core/base_mold_generator.py

@@ -398,14 +398,42 @@ class BaseMoldGenerator:
                 core = self._subtract_product_from_plate(b_plate, shape, "B板(回退)")
                 return cavity or a_plate, core or b_plate
 
-            logger.warning("回退方案也失败，使用最简方法")
-            cavity_op = BRepAlgoAPI_Cut(mold_block, shape)
-            cavity = cavity_op.Shape() if cavity_op.IsDone() else mold_block
-            return cavity, shape
+            logger.warning("回退方案也失败，使用最简A/B板切分（避免返回产品本体）")
+            center_z = (zmin + zmax) / 2
+            margin = 20
+            a_plate = BRepPrimAPI_MakeBox(
+                gp_Pnt(xmin - margin, ymin - margin, center_z),
+                gp_Pnt(xmax + margin, ymax + margin, zmax + margin)
+            ).Shape()
+            b_plate = BRepPrimAPI_MakeBox(
+                gp_Pnt(xmin - margin, ymin - margin, zmin - margin),
+                gp_Pnt(xmax + margin, ymax + margin, center_z)
+            ).Shape()
+
+            cavity = self._subtract_product_from_plate(a_plate, shape, "A板(最简)")
+            core = self._subtract_product_from_plate(b_plate, shape, "B板(最简)")
+            return cavity or a_plate, core or b_plate
 
         except Exception as e:
             logger.error(f"分模回退方案失败: {e}")
-            return shape, shape
+            # 最后兜底也返回模具半板，而不是产品本体，避免预览出现“三份产品”
+            try:
+                bbox = Bnd_Box()
+                brepbndlib.Add(shape, bbox)
+                xmin, ymin, zmin, xmax, ymax, zmax = bbox.Get()
+                center_z = (zmin + zmax) / 2
+                margin = 20
+                a_plate = BRepPrimAPI_MakeBox(
+                    gp_Pnt(xmin - margin, ymin - margin, center_z),
+                    gp_Pnt(xmax + margin, ymax + margin, zmax + margin)
+                ).Shape()
+                b_plate = BRepPrimAPI_MakeBox(
+                    gp_Pnt(xmin - margin, ymin - margin, zmin - margin),
+                    gp_Pnt(xmax + margin, ymax + margin, center_z)
+                ).Shape()
+                return a_plate, b_plate
+            except Exception:
+                return shape, shape
 
     def detect_insert_regions(self, shape: Any, analysis: Dict,
                                depth_threshold: float = 30.0,