A new dynamic path planning method in high dimensional workspace, radial based probabilistic roadmap motion (RBPRM) planning method, is presented. Different from general probabilistic roadmap motion planning methods, ...A new dynamic path planning method in high dimensional workspace, radial based probabilistic roadmap motion (RBPRM) planning method, is presented. Different from general probabilistic roadmap motion planning methods, it uses straight lines as long as possible to construct a path graph, so the final path obtained from the graph is relatively shorter and straighter. Experimental results show the efficiency of the algorithm in finding shorter paths in sparse environment.展开更多
According to the features of the turning simulation, a simplified Whitted lighti ng model is proposed based on the analysis of Phong and other local illumination model. Moreover, in order to obtain the natural lightin...According to the features of the turning simulation, a simplified Whitted lighti ng model is proposed based on the analysis of Phong and other local illumination model. Moreover, in order to obtain the natural lighting effects, local ray tra cing algorithm is given to calculate the light intensity of every position durin g the course of the simulation. This method can calculate the refresh area befor e calculating the intersection line, simulate the machining environment accurate ly and reduce the calculating time. Finally, an example of the virtual cutting s cene is shown to demonstrate the effects of the global illumination model. If th e CUP is 1.3 G and the internal memory is 128 M, the refreshing time of virtual turning scene can be reduced by nine times.This study plays an important role in the enrichment of the virtual manufacturing theory and the promotion of the dev elopment of the advanced manufacturing technology.展开更多
The study of marine data visualization is of great value. Marine data, due to its large scale, random variation and multiresolution in nature, are hard to be visualized and analyzed. Nowadays, constructing an ocean mo...The study of marine data visualization is of great value. Marine data, due to its large scale, random variation and multiresolution in nature, are hard to be visualized and analyzed. Nowadays, constructing an ocean model and visualizing model results have become some of the most important research topics of ‘Digital Ocean'. In this paper, a spherical ray casting method is developed to improve the traditional ray-casting algorithm and to make efficient use of GPUs. Aiming at the ocean current data, a 3D view-dependent line integral convolution method is used, in which the spatial frequency is adapted according to the distance from a camera. The study is based on a 3D virtual reality and visualization engine, namely the VV-Ocean. Some interactive operations are also provided to highlight the interesting structures and the characteristics of volumetric data. Finally, the marine data gathered in the East China Sea are displayed and analyzed. The results show that the method meets the requirements of real-time and interactive rendering.展开更多
文摘A new dynamic path planning method in high dimensional workspace, radial based probabilistic roadmap motion (RBPRM) planning method, is presented. Different from general probabilistic roadmap motion planning methods, it uses straight lines as long as possible to construct a path graph, so the final path obtained from the graph is relatively shorter and straighter. Experimental results show the efficiency of the algorithm in finding shorter paths in sparse environment.
文摘According to the features of the turning simulation, a simplified Whitted lighti ng model is proposed based on the analysis of Phong and other local illumination model. Moreover, in order to obtain the natural lighting effects, local ray tra cing algorithm is given to calculate the light intensity of every position durin g the course of the simulation. This method can calculate the refresh area befor e calculating the intersection line, simulate the machining environment accurate ly and reduce the calculating time. Finally, an example of the virtual cutting s cene is shown to demonstrate the effects of the global illumination model. If th e CUP is 1.3 G and the internal memory is 128 M, the refreshing time of virtual turning scene can be reduced by nine times.This study plays an important role in the enrichment of the virtual manufacturing theory and the promotion of the dev elopment of the advanced manufacturing technology.
基金supported by the Natural Science Foundation of China under Project 41076115the Global Change Research Program of China under project 2012CB955603the Public Science and Technology Research Funds of the Ocean under project 201005019
文摘The study of marine data visualization is of great value. Marine data, due to its large scale, random variation and multiresolution in nature, are hard to be visualized and analyzed. Nowadays, constructing an ocean model and visualizing model results have become some of the most important research topics of ‘Digital Ocean'. In this paper, a spherical ray casting method is developed to improve the traditional ray-casting algorithm and to make efficient use of GPUs. Aiming at the ocean current data, a 3D view-dependent line integral convolution method is used, in which the spatial frequency is adapted according to the distance from a camera. The study is based on a 3D virtual reality and visualization engine, namely the VV-Ocean. Some interactive operations are also provided to highlight the interesting structures and the characteristics of volumetric data. Finally, the marine data gathered in the East China Sea are displayed and analyzed. The results show that the method meets the requirements of real-time and interactive rendering.