diff --git a/post_pro/conv_obj.py b/post_pro/conv_obj.py
index 66528b1..41d7ff7 100644
--- a/post_pro/conv_obj.py
+++ b/post_pro/conv_obj.py
@@ -34,22 +34,17 @@ class ConvertOBJ:
             first_grid_dir, "odm_orthophoto", "odm_orthophoto_log.txt")
         self.ref_east, self.ref_north = self.read_utm_offset(log_file)
 
-        # 以第一个grid计算高度的偏移量
-        min_z = self.get_min_z_from_obj(os.path.join(first_grid_dir, 'odm_texturing', 'odm_textured_model_geo.obj'))
-        min_25d_z = self.get_min_z_from_obj(os.path.join(first_grid_dir, 'odm_texturing_25d', 'odm_textured_model_geo.obj'))
-        high = min_25d_z - min_z
-
         for grid_id in grid_points.keys():
             try:
                 self._convert_single_grid(grid_id, grid_points)
             except Exception as e:
                 self.logger.error(f"网格 {grid_id} 转换失败: {str(e)}")
 
-        self._create_merged_metadata(high)
+        self._create_merged_metadata()
 
     def _convert_single_grid(self, grid_id, grid_points):
         """转换单个网格的OBJ文件"""
-        # 1. 构建相关路径
+        # 构建相关路径
         grid_name = f"grid_{grid_id[0]}_{grid_id[1]}"
         project_dir = os.path.join(self.output_dir, grid_name, "project")
         texturing_dir = os.path.join(project_dir, "odm_texturing")
@@ -59,13 +54,18 @@ class ConvertOBJ:
             project_dir, "odm_orthophoto", "odm_orthophoto_log.txt")
         os.makedirs(texturing_dst_dir, exist_ok=True)
 
-        # 2. 在新文件夹下，利用UTM偏移量，修改obj文件顶点坐标，纹理文件下采样
+        # 修改obj文件z坐标的值
+        min_25d_z = self.get_min_z_from_obj(os.path.join(
+            project_dir, 'odm_texturing_25d', 'odm_textured_model_geo.obj'))
+        self.modify_z_in_obj(texturing_dir, min_25d_z)
+
+        # 在新文件夹下，利用UTM偏移量，修改obj文件顶点坐标，纹理文件下采样
         utm_offset = self.read_utm_offset(log_file)
         modified_obj = self.modify_obj_coordinates(
             texturing_dir, texturing_dst_dir, utm_offset)
         self.downsample_texture(texturing_dir, texturing_dst_dir)
 
-        # 3. 执行格式转换，Linux下osgconv有问题，记得注释掉
+        # 执行格式转换，Linux下osgconv有问题，记得注释掉
         self.logger.info(f"开始转换网格 {grid_id} 的OBJ文件")
         output_osgb = os.path.join(texturing_dst_dir, "Tile.osgb")
         cmd = (
@@ -79,7 +79,7 @@ class ConvertOBJ:
         except subprocess.CalledProcessError as e:
             raise RuntimeError(f"OSGB转换失败: {str(e)}")
 
-        # 5. 创建OSGB目录结构，复制文件
+        # 创建OSGB目录结构，复制文件
         osgb_base_dir = os.path.join(self.output_dir, "osgb")
         data_dir = os.path.join(osgb_base_dir, "Data")
         tile_dir = os.path.join(data_dir, f"Tile_{grid_id[0]}_{grid_id[1]}")
@@ -88,7 +88,7 @@ class ConvertOBJ:
             tile_dir, f"Tile_{grid_id[0]}_{grid_id[1]}.osgb")
         shutil.copy2(output_osgb, target_osgb)
 
-    def _create_merged_metadata(self, high):
+    def _create_merged_metadata(self):
         """创建合并后的metadata.xml文件"""
         # 转换为WGS84经纬度
         center_lon, center_lat = self.transformer.transform(
@@ -96,7 +96,7 @@ class ConvertOBJ:
         metadata_content = f"""<?xml version="1.0" encoding="utf-8"?>
 <ModelMetadata version="1">
     <SRS>EPSG:4326</SRS>
-    <SRSOrigin>{center_lon},{center_lat},{high}</SRSOrigin>
+    <SRSOrigin>{center_lon},{center_lat},0</SRSOrigin>
         <Texture>
             <ColorSource>Visible</ColorSource>
         </Texture>
@@ -130,7 +130,8 @@ class ConvertOBJ:
 
     def modify_obj_coordinates(self, texturing_dir: str, texturing_dst_dir: str, utm_offset: tuple) -> str:
         """修改obj文件中的顶点坐标，使用相对坐标系"""
-        obj_file = os.path.join(texturing_dir, "odm_textured_model_geo.obj")
+        obj_file = os.path.join(
+            texturing_dir, "odm_textured_model_modified.obj")
         obj_dst_file = os.path.join(
             texturing_dst_dir, "odm_textured_model_geo_utm.obj")
         if not os.path.exists(obj_file):
@@ -231,3 +232,22 @@ class ConvertOBJ:
                     if z < min_z:
                         min_z = z
         return min_z
+
+    def modify_z_in_obj(self, texturing_dir, min_25d_z):
+        obj_file = os.path.join(texturing_dir, 'odm_textured_model_geo.obj')
+        output_file = os.path.join(
+            texturing_dir, 'odm_textured_model_modified.obj')
+        with open(obj_file, 'r') as f_in, open(output_file, 'w') as f_out:
+            for line in f_in:
+                if line.startswith('v '):  # 顶点坐标行
+                    parts = line.strip().split()
+                    x = float(parts[1])
+                    y = float(parts[2])
+                    z = float(parts[3])
+
+                    if z < min_25d_z:
+                        z = min_25d_z
+
+                    f_out.write(f"v {x} {y} {z}\n")
+                else:
+                    f_out.write(line)