| In this thesis, a human-computer interaction approach for the generation of geometric shapes via multi-sensory user interface of a Virtual Reality (VR) based System is presented. Through the use of VR devices, geometric design can be more effectively inputted into the Computer-Aided Design (CAD) system in a natural and physically intuitive way. The focus of this research is on determining a set of efficient interaction approach by using the combinations of auditory, tactile, and visual sensory modalities to accomplish typical CAD tasks. In order to evaluate the efficiency of the proposed interaction approaches, prototypical VR-CAD systems are implemented as part of this research. A series of interface tests were performed on the prototypical systems to determine the relative efficiency of the interaction approaches. Interface test results indicate that auditory input, voice commands, are effective in operation activations such as rotating viewpoint, creating/deleting entities in the virtual environment. The tactile input, hand actions/motions, are found to be highly efficient for navigation, entity selection, complex 3D manipulations of entities and dynamically changing entity's dimension in the VR-CAD system. It is also determined that building simple geometry shapes containing canonical forms, such as blocks, cylinders, spheres, etc, using VR interface results in a speedup of 1.5 to 2.0 times over the traditional interface. For more complex shapes, the speedup factor is about 3 to 4 times. This indicates that there are greater benefits when designing complex geometry shapes than design simpler shapes in a VR CAD system. The contribution of this research lies on setting a new paradigm for multi-sensory input output interaction approaches of a VR based CAD system to provide an easy-to-use and effective tool for product shape design. |
