Inferring 3D models from freehand sketches and constraints

This paper describes 'Quick-sketch', a 2D and 3D modelling tool for pen-based computers. Users of this system define a model by simple pen strokes, drawn directly on the screen of a pen-based PC. Exact shapes and geometric relationships are interpreted from the sketch. The system can also be used to sketch 3D solid objects and B-spline surfaces. These objects may be refined by defining 2D and 3D geometric constraints. A novel graph-based constraint solver is used to establish the geometric relationships, or to maintain them when manipulating the objects interactively. The approach presented here is a first step towards a conceptual design system. Quick-sketch can be used as a hand sketching front-end to more sophisticated modelling, rendering or animation systems. Copyright (C) 1996 Elsevier Science Ltd