A Study of Real-time Computation for Physical Constraints in VR Environment

• Main Authors: Li ,Tzu Sheng, 李自升
• Other Authors: Tsai, Ming Dar
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/53694582856104969264

碩士 === 中原大學 === 資訊工程研究所 === 84 === In this thesis, we studied physically-based constraints on a virtual reality environment. The physically-based modeling provide us a much greater complexity and realism than the ones by only geometric and kinematic descriptions. In our system, we compute the real-time physical responses among objects. The system incorporated physical models have many potential applications beyond graphics, as in mechanical CAD, robotics, assembling system or computer vision. We adopted a contact-force computing algorithm that describe contact constraints as preventing solid objects from moving through other ones. This algorithm is fast enough to let users interactively manipulate rigid objects as in virtual environments. Contact constraints come as objects get into contacts; therefore, the system employed collision tests and computed states of objects to know when creating a new contact constraint. The sates of objects are solved by the fourth order Runge-Kutta method. For collision detection, we adopted an algorithm that exploited geometric coherence. We implemented the above algorithms by using VRML descriptions. VRML is going to be standard language for virtual reality environments. We studied from what descriptions of VRML we can obtain compute physical constraints and how to take suitable numerical intervals for real-time response purposes. We also suggested how to describe the physical properties of objects in VRML.