Question: I am trying to write a python script that will convert triangular-mesh objects to quad-mesh objects.  For example, image (a) will be my input (.obj/.stl) file and image (b) will be the output. I am a noob with mesh-algorithms or how they work all together. So, far this is the script I have written: import bpy inp = 'mushroom-shelve-1-merged.obj' # Load the triangle mesh OBJ file bpy.ops.import_scene.obj(filepath=inp, use_smooth_groups=False, use_image_search=False) # Get the imported mesh obj = bpy.context.selected_objects[0] # Convert triangles to quads # The `beauty` parameter can be set to False if desired bpy.ops.object.mode_set(mode='EDIT') bpy.ops.mesh.select_all(action='SELECT') bpy.ops.mesh.tris_convert_to_quads(beauty=True) bpy.ops.object.mode_set(mode='OBJECT') # Export to OBJ with quads bpy.ops.export_scene.obj(filepath='quad_mesh.obj')  This results in the following error: Traceback (most recent call last): File "/home/arrafi/mesh-convert-application/test.py", line 8, in <module> bpy.ops.import_scene.obj(filepath=inp, File "/home/arrafi/mesh-convert-application/venv/lib/python3.10/site-packages/bpy/4.0/scripts/modules/bpy/ops.py", line 109, in __call__ ret = _op_call(self.idname_py(), kw) AttributeError: Calling operator "bpy.ops.import_scene.obj" error, could not be found  Any help with what I am doing wrong here would be greatly appreciated.  Also please provide your suggestions for if you know any better way to convert triangular-mesh to quad-mesh with Python. If you guys know of any API that I can call with python to do the conversion, that would work too. 

Answer: Turns out bpy.ops.import_scene.obj was removed at bpy==4 which is the latest blender-api for python, hence the error. In bpy>4 you have to use bpy.ops.wm.obj_import(filepath='') I just downgraded to bpy==3.60 to import object directly in the current scene. pip install bpy==3.6.0  I also modified my script to take input of .obj files in triangular-mesh and then convert the mesh to quadrilateral, then export as both stl and obj. Here's my working script: def convert_tris_to_quads(obj_path, export_folder): try: filename = os.path.basename(obj_path).split('.')[0] logging.info(f"Importing {obj_path}") bpy.ops.object.select_all(action='DESELECT') bpy.ops.object.select_by_type(type='MESH') bpy.ops.object.delete() bpy.ops.import_scene.obj(filepath=obj_path) print("current objects in the scene: ", [obj for obj in bpy.context.scene.objects]) for obj in bpy.context.selected_objects: bpy.context.view_layer.objects.active = obj logging.info("Converting mesh") bpy.ops.object.mode_set(mode='EDIT') bpy.ops.mesh.select_all(action='SELECT') bpy.ops.mesh.tris_convert_to_quads() bpy.ops.object.mode_set(mode='OBJECT') # Export to OBJ obj_export_path = export_folder + filename + '_quad.obj' logging.info(f"Exporting OBJ to {obj_export_path}") bpy.ops.export_scene.obj(filepath=obj_export_path, use_selection=True) # Export to STL stl_export_path = export_folder + filename + '_quad.stl' logging.info(f"Exporting STL to {stl_export_path}") bpy.ops.export_mesh.stl(filepath=stl_export_path, use_selection=True) except Exception as e: logging.error(f"Error processing {obj_path}: {e}") return False  This still might not be the best approach to this, so do let me know if anyone know any better approach.