An approach to solid modeling in a semi-immersive virtual environment

Researches on using virtual reality (VR) to support computer-aided design a re rapidly increasing in recent years. This is because VR techniques are ve ry helpful in improving the interactivity and 3D visualization function of CAD systems. In this paper, we present an approach to solid modeling in a s emi-immersive virtual environment. The approach allows users to create, man ipulate and visualize a precise solid model by direct 3D manipulations and voice commands in a virtual environment with a 3D input device. In the appr oach, to make the solid model created and modified by direct 3D manipulatio ns precise, real-time constraint recognition, propagation and solution algo rithms are developed and utilized. An extended solid model is also adopted to effectively support the solid modeling by direct 3D manipulations. The e xperiment shows that the approach enables users to conduct solid modeling i ntuitively, effectively and accurately, thus can be used for both early sta ge design and detailed design. (C) 2000 Elsevier Science Ltd. All rights re served.