A method and system for three-dimensional (3D) surface sketching are provided. A 3D scanner scans an outer surface of a physical object and outputs data representative of the outer surface. A processor generates, based on the received data, a 3D model of the object and outputs a 3D rendering of the object. A display displays the 3D rendering of the object. An input device physically traces over a portion of the outer surface of the object and a tracking device tracks a positioning of the input device as the input device physically traces over the portion of the outer surface of the object. The processor receives data representative of at least one spatial position of the input device, augments the 3D rendering of the object based at least in part on the data and outputs the augmented 3D rendering to the display.