Implicit mapping mechanism in pen-based three-dimensional modeling system

The pen-based three-dimensional modeling system supports the user to sketch freely based on pen-paper metaphor so as to express three-dimensional models, and carries out corresponding three-dimensional modeling according to the user’s interaction intention. A kind of implicit mapping mechanism was proposed according to the characteristics of pen-based three-dimensional modeling technology. Two virtual projecting planes, which were vertical reciprocally, were constructed dynamically through analyzing the two-dimensional stroke and the interaction context so as to transform the two-dimensional stroke to three-dimensional spatial information smoothly. A method of coordinate increment replacement was proposed to dissolve the problems of mapping in ultimate positions. As a result, not only the problems of coordinate mapping from two-dimensional stroke tothree-dimensional spatial information in ultimate positions were settled, but also the user could sketch more freely to express much more complicated three-dimensional models. The user could be free from fussy and complicated operations by implicit mapping mechanism and concentrate on expressing his creative inspiration. It has been validated in a prototype system, PenSketch3D, with promising effect.