feat: support PLY meshes in vehicle registration

alg/整车配准v1.3/translate_align_pointcloud_to_cad.py

@@ -173,6 +173,33 @@ def step_to_open3d_mesh(step_path, mesh_deflection=0.1):
     return mesh
 
 
+def load_cad_mesh(cad_path, mesh_deflection=0.1):
+    """根据后缀加载 CAD mesh：STEP 走 OCC 离散化，PLY 直接读取三角网格。"""
+    ext = os.path.splitext(cad_path)[1].lower()
+
+    if ext in (".step", ".stp"):
+        return step_to_open3d_mesh(cad_path, mesh_deflection=mesh_deflection)
+
+    if ext == ".ply":
+        print(f"[INFO] Loading CAD mesh from PLY: {cad_path}")
+        mesh = o3d.io.read_triangle_mesh(cad_path)
+        if len(mesh.vertices) == 0 or len(mesh.triangles) == 0:
+            raise RuntimeError(f"PLY CAD mesh 为空或读取失败: {cad_path}")
+
+        mesh.remove_duplicated_vertices()
+        mesh.remove_duplicated_triangles()
+        mesh.remove_degenerate_triangles()
+        mesh.compute_vertex_normals()
+
+        print(
+            f"[OK] PLY CAD mesh loaded: {len(mesh.vertices)} vertices, "
+            f"{len(mesh.triangles)} triangles"
+        )
+        return mesh
+
+    raise RuntimeError(f"不支持的 CAD 格式: {cad_path}（仅支持 .step/.stp/.ply）")
+
+
 # ============================================================
 # 工具函数
 # ============================================================
@@ -529,7 +556,7 @@ def translate_align_by_front_tail(
                 cad_pcd = None
 
     if cad_pcd is None:
-        cad_mesh = step_to_open3d_mesh(
+        cad_mesh = load_cad_mesh(
             cad_path,
             mesh_deflection=mesh_deflection
         )