1. A computer-implemented method for interactively modifying a 3D object modeled by a geometry mesh, the method comprising: displaying the 3D object on a display; electronically receiving a user selection of a reshaping action to be applied to the 3D object; receiving user input to mask a first region of the displayed 3D object that is not to be affected by the received selected reshaping action, wherein a second region of the displayed 3D object is left as unmasked; drawing an action line on a portion of the unmasked region of the displayed 3D object where a re-shaping action to be applied to the 3D object, in response to a user command specifying a start point and an end point, wherein the action line defines an arbitrary axis relative to which a reshaping action is to applied and wherein the action line is placed on the unmasked region of the portion of the displayed 3D object; electronically receiving a user selection of a selected point associated with the action line; electronically detecting movement of a user input device with respect to the selected point; and electronically applying the selected reshaping action on at least a portion of the unmasked region of the 3D object based on the detected movement of the user input device and with reference to the action line, wherein the re-shaping action does not require generation of a virtual skeleton of the displayed 3D object.