A framework for User-Assisted Sketch-Based Fitting of Geometric Primitives

In this paper, we present a user-assisted sketch-based
framework to extract hi-level primitives (e.g. columns
or staircases) from scanned3D models of an architectural complex. The framework offers a unified level
of representation of the hi-level primitives, so that new
types of primitives can be easily added as plug-ins to the
main engine. Primitives are fitted with a user-assisted
procedure: the user suggests the approximate location
of the primitive by means of simple mouse gestures,
sketched over a rendering of the model. The viewpoint
that was selected prior to the sketching is also taken in
consideration as hints on the orientation and size of the
primitive. The engine performs a GPU assisted fitting
and the result is shown in real time to the user. Ad-hoc
gestures cause the system to add and fit groups of primitive in one go (e.g. a column complex, or a sequence
of windows).