Geo-graphic code representation of 3-D objects from their pictorial drawings

The technique of geographic encoding for the representation of a 3-D object is introduced in this paper. The geographic codes consist of the number of visible vertices and surfaces, the vertex-surface description, the vertex-surface vector, the vertex-type description, and the vertex-link code. A novel method for automatic surface extraction from the pictorial drawing of a 3-D object is presented. This method converts a pictorial drawing into surface trees. For each candidate visible surface, a surface tree is generated from which a visible surface is automatically identified via tree tracing. The extracted surfaces are orderly arranged to generate the vertex-surface description (VSD) for the 3-D object. The other geographic codes are automatically generated from the vertex-surface description.