Computational Science and Its Applications - ICCSA 2003,
International Conference, Montreal, Canada, May 18-21, 2003,
Proceedings, Part III. LNCS 2669. Springer. 2003, 721-730.
This contribution introduces a new framework for assembly modeling in Virtual Reality.
Aiming at an easy instructability of the virtual environment, the framework provides
a task-level interface which directly maps logical assembly commands to corresponding
changes in the geometry scene. For example, the visual assembly of two parts is
achieved given only a single command 'connect(a,b)'. This is in contrast to the
assembly modeling style of conventional CAD systems which forces the designer to break
down each conceptual assembly task into a series of lower-level subtasks. The proposed
framework consists of two parts: (1) A knowledge-based model of connection-sensitive
part features ("ports") and the connections between them; and, (2), a set of algorithms
that define the task-level interface for assembly, disassembly, and adjustment
operations. All algorithms are computationally efficient and easily meet the real-time
requirements of virtual environments. At the user interface, both direct manipulation
and directive interfaces, e.g. based on natural language instructions are supported.
A family of implemented VR-systems, including CAVE and Internet-based applications,
demonstrates the feasibility of the approach.