Discrimination between command and drawing strokes for sketch-based CAD interfaces based on fuzzy spline curve fragmentation

In this paper, we propose a command stroke (CS)/ drawing stroke (DS) discriminator that distinguishes input penstrokes into CS for command input and DS for geometric-shape input, with the aim of realizing command input by penstrokes in sketch-based computer-aided design (CAD) interfaces. This discriminator utilizes the fuzzy spline curve fragmentation, and is characterized by its ability to discriminate in real-time without relying on textual information or geometric features. By introducing the discriminator into a sketch-based CAD interface and experimentally implementing several command inputs, we demonstrated through drawing experiments that both the command and geometric-shape inputs can be implemented seamlessly with sketch-based input to efficiently complete technical drawings.