Creation of freeform solid models in virtual reality

A novel method has been developed using a virtual reality (VR) environment to create solid models with freeform surfaces. The VR environment emulates the physical environment for creating freeform objects, i.e. the freeform m odel is created in a virtual environment by shaping a virtual workpiece wit h a variety of virtual tools. The trajectories of the virtual tools are gen erated by the designer's hand movements and they are obtained by recording the position and orientation of the motion tracker mounted on a device held by the hand. A haptic device can be worn by the designer to provide a feel of the model creation process. In the mathematical algorithm, the swept vo lumes of the design tools are computed from the tools' geometric data and t rajectories. Boolean operations are then performed on the swept volumes of the virtual tools and the virtual workpiece to create the design model. If the virtual tools used have the same geometry as the real tools used in num erically controlled (NC) machining, their trajectories in the model creatio n process can be postprocessed and used as feasible trajectories in actual NC machining to fabricate the design model.