Thursday, February 18th, Volen 101, 2:10-3:10 pm. (Refreshments at 2:00pm)
This talk will describe a CAD interface for 3D conceptual design based on freehand sketching. The interface is based on reconstruction of a 3D CAD model from a single freehand sketch. There are several difficulties in implementing this kind of interface. The primary difficulty is that the reconstruction is mathematically indeterminate because the flat sketch (projection) lacks three-dimensional depth information. Inaccuracies inherent in the freehand sketch intensify the difficulty.
The proposed reconstruction algorithm operates in several stages. First, the raw sketch is analyzed, and basic geometrical entities (lines, elliptic arcs and corners) in the projection are identified and smoothed. These entities are then linked to form an edge-vertex graph representing the two-dimensional topology of the object's projection. The three-dimensional object is then reconstructed using implicit spatial cues in the sketch plane. These cues originate from two main sources: (a) statistical geometrical regularities among entities in the sketch plane, and (b) sketch topology. The talk will discuss these principles and provide some examples from an implementation.
Host: Jordan Pollack