Sketch Input of Engineering Euclidean Solid Models

Abstract —This position paper describes some open problems of sketch input of engineering Euclidean solid models. After a brief historical introduction, we discuss traditional design using pencil and paper, and how this paradigm has been adapted (or forgotten) by various current approaches to computer interpretation of sketches. We discuss three particular open problems, those of modalities, annotations, and assemblies. We also analyse current perception-based approaches in order to identify the most important areas in which further work is needed: detection of geometrical, perceptual and manufacturing cues, and a taxonomy of cue interdependencies which would prevent incompleteness and contradictions. Index Terms—Pen computing, Sketch-based modelling, Sketching interface, Cues. I. I NTRODUCTION Pen computing refers to those computer user interfaces where users interact with computers by means of pens which guide pointers moving around a screen. In this paper, such interfaces are considered distinct from classic keyboard/ display/mouse environments only as far as they are used to simulate the behaviour of actual paper and pencil. We are only interested in "virtual" paper and pencil which allows free sketching and annotating, not in the "pointing mode" of WIMP environments. Similarly, we are interested in handwriting as far as it conveys