A SOPHISTICATED MANIPULATION AID IN A VIRTUAL ENVIRONMENT USING DYNAMIC CONSTRAINTS AMONG OBJECT FACES

A natural and intuitive method is proposed to help a user manipulate a n object in a virtual environment. The method does not need to assign special properties to the object faces in advance and does not require special hardware. Instead, it uses only the visual constraints of mot ion among object faces that are dynamically selected by a real-time co llision detection method while the user manipulates the object. By con straining more than two faces during the user's manipulation, the prop osed method provides an efficient tool for complicated manipulation ta sks. First, the method of manipulation aid is described. Then several experiments demonstrate the effectiveness of this method, particularly when the user is requested to precisely place a virtual object in a c ertain location. Finally, as an application of the proposed manipulati on aid, an experiment is conducted to compare the performances of a ta sk (constructing a simple toy) in a real versus a virtual environment. Results show that the distance accuracy and completion time of the vi rtual task with the manipulation aid is close to that of the real task .