Geometry standardization of arbitrary multi-stroke sketching

For the freehand sketching in 3D of automotive styling, this paper has investigated the geometry standardization through the identifications and fittings of the geometries drawn by arbitrary strokes. The standard geometries can be established by freehand sketching in 3D. The working process has been proposed to achieve the goal of identifying the standard geometries automatically. The standardization has been realized in three levels for arbitrary sketching. Firstly, the strokes to be combined into a single stroke are arbitrary; secondly, the strokes to form a standard geometry are arbitrary; and thirdly, the modifications of strokes are arbitrary.