Abstract
An input device of space design adapted to a graphic system is disclosed. The input device includes a light emitting module and a photography module, wherein the light emitting module includes a first transceiver unit and a light source, and the photography module includes a second transceiver unit, an image retrieving unit and a light tracing unit. The first and second transceiver units respectively communicate the light emitting module and the photography module with the graphic system. When the light emitting module receives a first input command, the light source emits a light to a reality environment. The image retrieving unit films the reality environment and outputs a background image to the graphic system so that the graphic system can display a three-dimensional (3D) graphic corresponding to the background image. The light tracing unit traces the moving path of the emitted light and generates a first control signal to the graphic system so that the graphic system draws an object in the 3D graphic.