A System for Constructing Boundary Representation Solid Models from a Two-Dimensional Sketch — Frontal Geometry and Sketch Categorisation

This paper discusses research results useful for producing a system which converts a two-dimensional computer sketch of a single homogeneous polyhedral object into a boundary representation solid model. An overview of our approach to such a system and its main algorithms is presented elsewhere. This paper gives more detail of some of the algorithms for categorising sketches according to the type of object drawn and generating preliminary geometry for the part of the object visible in the sketch. It discusses various alternative methods considered and explains which were chosen and why. The topics covered in detail are parallel line detection, preliminary geometry, identification of symmetries and regularities, and sketch categorisation.