The sketch is first tested for the presence of one or more
underlying axis systems using a histogram of the angles
of the strokes in the sketch. The underlying axis systems
are then reconstructed, and used to determine the depth of
the sketch vertices. This process is described in more detail
in these proceedings (Kang, Masry, & Lipson 2004).
While this approach can reconstruct complex shapes very
quickly, it cannot be used with sketches that do not conform
to an underlying axis system, or that have disconnected
components.