Sketching space

In this paper, we present a sketch modelling system which we call Stilton. The program resembles a desktop VRML browser, allowing a user to navigate a three-dimensional model in a perspective projection, or panoramic photogra phs, which the program maps onto the scene as a "floor" and "walls". We pla ce an imaginary two-dimensional drawing plane in front of the user, and any geometric information that user sketches onto this plane may be reconstruc ted to form solid objects through an optimisation process. We show how the system can be used to reconstruct geometry from panoramic images, or to add new objects to an existing model. While panoramic imaging can greatly assi st with some aspects of site familiarisation and qualitative assessment of a site, without the addition of some foreground geometry they offer only li mited utility in a design context. Therefore, we suggest that the system ma y be of use in "just-in-time" CAD recovery of complex environments, such as shop floors, or construction sites, by recovering objects through sketched overlays, where other methods such as automatic line-retrieval may be impo ssible. The result of using the system in this manner is the "sketching of space" - sketching out a volume around the user - and once the geometry has been recovered, the designer is free to quickly sketch design ideas into t he newly constructed context, or analyse the space around them. Although en d-user trials have not, as yet, been undertaken we believe that this implem entation may afford a user-interface that is both accessible and robust, an d that the rapid growth of pen-computing devices will further stimulate act ivity in this area. (C) 2000 Elsevier Science Ltd. All rights reserved.