为了实现国内城市实时天气的三维动态可视化显示,以Google Earth为二次开发平台,在.NET环境下实现系统的设计。通过调用Weather Web Service,解析得到天气信息,利用OpenGL以物理规律和粒子系统理论为依据模拟天气现象。查询时,在Google Earth的城市界面背景上,显示出查询地点实时天气对应的天气动画。实验结果表明:该系统能够使得传统视景仿真得到的雨雪等天气效果实时更新,并且实现了天气信息与地理信息的有机叠加,具有良好的实时性和直观性。
The modelling and simulation of deformable objects is a challenging topic in the field of haptic rendering between human and virtual environment.In this paper,a novel and efficient layered rhombus-chain-connected haptic deformation model based on physics is proposed for an excellent haptic rendering.During the modelling,the accumulation of relative displacements in every chain structure unit in each layer is equal to the deformation on the virtual object surface,and the resultant force of corresponding springs is equivalent to the external force.The layered rhombus-chain-connected model is convenient and fast to calculate,and can satisfy real-time requirement due to its simple nature.Simulation experiments in virtual human liver based on the proposed model are conducted,and the results demonstrate that our model provides stable and realistic haptic feeling in real time.Meanwhile,the display result is vivid.
To improve the accuracy and interactivity of soft tissue deformation simulation,a new plate spring model based on physics is proposed.The model is parameterized and thus can be adapted to simulate different organs.Different soft tissues are modeled by changing the width,number of pieces,thickness,and length of a single plate spring.In this paper,the structural design,calculation of soft tissue deformation and real-time feedback operations of our system are also introduced.To evaluate the feasibility of the system and validate the model,an experimental system of haptic interaction,in which users can use virtual hands to pull virtual brain tissues,is built using PHANTOM OMNI devices.Experimental results show that the proposed system is stable,accurate and promising for modeling instantaneous soft tissue deformation.
