Ponència presentada al STAG17: Smart tools and Applications in Graphics, celebrat a Catania (Itàlia) 11-12 setembre 2017This paper describes a new “envelope” approach for detecting object perimeters in line-drawings vectorised from
sketches of polyhedral objects.
Existing approaches for extracting contours from digital images are unsuitable for Sketch-Based Modelling, as they
calculate where the contour is, but not which elements of the line-drawing belong to it.
In our approach, the perimeter is described in terms of lines and junctions (including intersections and T-junctions)
of the original line drawing
