# CONVTONURBS [GstarCAD 2022](Help%20System/GSTARCAD/2022/Index.md) → [What's new](Help%20System/GSTARCAD/2022/What's%20new/(What's%20new).md) → [Additional Pages](Help%20System/GSTARCAD/2022/What's%20new/Additional%20Pages/(Additional%20Pages).md) You can input CONVTONURBS command or click Ribbon – Surface – CV – Convert to NURBS to convert solids and procedural surfaces to NURBS surfaces. You can also convert meshes to NURBS surfaces after converting them to a solid or surface by CONVTOSOLID or CONVTOSURFACE command.  There are a series of new functionalities for NURBS control vertices editing and display.  **SHOW CV**: Shows control vertices. You can adjust the NURBS surfaces by clicking the control vertices, you will get 4 options (Base point, Copy, Undo, Exit) in your command line and dynamic input box. - Base point: Moves your control vertices according to the base point and second point you choose. - Copy: Copies a new NURBS surface and move it, the original surface won’t be deleted. - Undo: Cancels the previous step. - Exit: Stops adjusting control vertices. **HIDE CV**: Hides control vertices. **ADD**: Adds control vertices. After selecting the object, you will get 2 options ( insert Knots, Direction) to add control vertices and set the position. - Insert Knots: Turns off the display of control vertices and allows you to place a point directly on a surface. This option only displays if you select a surface; it does not display for splines. - Direction: Specifies whether to add control vertices in the U or V direction. This option only displays if you select a surface; it does not display for splines. **REMOVE**: Removes control vertices. **DELOBJ** :System Variable, when sets the value to 0, the defining objects won’t be deleted, when the value is -3, there will be a two options for users to choose delete or not, when it is 3, the defining objects will be deleted.