CADDM

访问量:8320

Graphics and visualizatin

  • Real-time rendering of large-scale static scene

    Wang Shaohua;Li Sheng;Lai Shunnan;

    In virtual simulation application, it is often necessary to use Open GL to render large-scale 3D static scenes including urban architectures. Each scene unit generally has individual vertex data and texture. For large-scale data set, it is hard to render all scene units simultaneously. We need to render part of the scene separately, which is called the scene partition and culling. In general, we partition the whole scene into different units on the CPU. We present a scheme that optimize the GPU rendering pipeline to cull the large-scale static scene, which will reduce the CPU suspending time and take full advantage of GPU computing advantages to speed up the rendering efficiency.

    2017年02期 v.27 1-6页 [查看摘要][在线阅读][下载 2053K]
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  • A stamp based exploration framework for numerical weather forecast

    Song Yibo;Chen Li;Liao Hongsen;Yong Junhai;

    Numerical weather simulation data usually comprises various meteorological variables, such as precipitation, temperature and pressure. In practical applications, data generated with several different numerical simulation models are usually used together by forecasters to generate the final forecast. However, it is difficult for forecasters to obtain a clear view of all the data due to its complexity. This has been a great limitation for domain experts to take advantage of all the data in their routine work. In order to help explore the multi-variate and multi-model data, we propose a stamp based exploration framework to assist domain experts in analyzing the data. The framework is used to assist domain experts in detecting the bias patterns between numerical simulation data and observation data. The exploration pipeline originates from a single meteorological variable and extends to multiple variables under the guidance of a designed stamp board. Regional data patterns can be detected by analyzing distinctive stamps on the board or generating extending stamps using the Boolean set operations. Experiment results show that some meteorological phenomena and regional data patterns can be easily detected through the exploration. These can help domain experts conduct the data analysis efficiently and further guide forecasters in producing reliable weather forecast.

    2017年02期 v.27 7-15页 [查看摘要][在线阅读][下载 8013K]
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Geometric design and computing

  • Semantic-driven method for designing 3D busbars

    Shi Kanle;Zhu Zixu;Wu Zijian;Zhang Hui;Yong Junhai;

    Traditional busbar design is inefficient, costly, and error-prone because of frequent changes of requirements. This paper proposes a semantic-driven method for designing 3D busbars to solve this problem. The design process contains two main parts, namely, semantic-driven routing design and automatic routing segmentation. Semantic-driven routing design creates a relation table between electrical semantics and 3D modeling parameters, as well as helps designers create routings efficiently using electrical parameters as input. Automatic routing segmentation can convert routings into busbar segments that also include manufacturing information. Because the design operations are associated with one another, the resulting busbars can automatically be changed in real time when requirements are changed.

    2017年02期 v.27 16-23页 [查看摘要][在线阅读][下载 1704K]
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  • Isometrically subdivisible tetrahedra

    Li Erbo;Li Zhi;Li Hua;

    It is well known that a triangle can be divided by mid-point refinement into four sub-triangles with the same shape. Similarly, a tetrahedron can be parted into eight subtetrahedra, which are generally not uniform in shape. This paper proves that there exist a set of tetrahedra, which is called isometrically subdivisible tetrahedra(IST) and can be divided into eight isometric subtetrahedra, including identical and reflection ones. And a new classification of tetrahedra is put forward, based on which all tetrahedra can be categorized into 26 classes according to both the number of maximum equal edges and topological relations. The IST belongs only to three of the classes. That result provides a new viewpoint of spatial structure and may be used to tile or subdivide space uniformly or isometrically.

    2017年02期 v.27 24-31页 [查看摘要][在线阅读][下载 983K]
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  • Automatic wiring method for switchgear design

    Shi Kanle;Gao Ying;Wu Zijian;Zhang Hui;Yong Junhai;

    An automatic 3D wiring method for switchgear design is proposed in this paper. First, wiring constraints are created, and a corresponding evaluation model is proposed. Then, based on the structure of the cabinet, we propose a contour expansion scheme to construct rough paths. Different wiring features of the switchgear are used to connect rough local paths. All the paths are represented in a uniform data structure and forma path network. Finally, an improved A* algorithm is used to search the wiring path between the components in the routing network; the evaluation model is considered as heuristic rules for path searching. The result can satisfy the practical requirements of switchgear design. Experimental results are also provided.

    2017年02期 v.27 32-38页 [查看摘要][在线阅读][下载 1059K]
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Applized technology of CAD/CAT/CAM/CG

  • Fast portrait automatic segmentation with coarse-to-fine CNNs

    Zhang Xijin;Li Ruilong;Zhang Songhai;

    In this paper, we propose a coarse-to-fine convolutional network framework designed with problem specific knowledge for fast automatic portrait segmentation. We built up a dataset of 7 100 portrait images which are frames from personal live show videos. The proposed network includes a coarse network which can learn global information and a fine network which utilizes local information to refine the coarse output. Additionally, an auxiliary contour loss is introduced to help training the coarse network. The proposed framework shows higher accuracy than the widely-used fully convolutional network. With light-weight post-processing, the predicted foreground mask can be used in real-time portrait video editing tasks such as background replacement.

    2017年02期 v.27 39-49页 [查看摘要][在线阅读][下载 20872K]
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  • A method for measuring pilot workload based on task analysis

    Liu Sichao;Tian Ling;Huang Zhongshan;

    This paper presents a method for measuring pilot workload based on task analysis in order that the cockpit can be designed more reasonably. In addition, a prototype system is developed to use this method for the assessment of pilot workload. The method breaks the pilot's mission into several phases, segments, functions and tasks. And break pilot workload into 6 components using Wickens' "multi-resource theory", which are vision(V), vision goggles(G), auditory sensation(A), cognitive activity(C), psychomotor activity(P) and kinesthesis(K). All missions consist of those tasks and each task have 6 workload components. The workload components for each task have been acquired by a study on many pilots, so workload can be assessed. A mission analysis database is built, and the prototype system can simulate pilot's flight process and evaluate workload.

    2017年02期 v.27 50-56页 [查看摘要][在线阅读][下载 549K]
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  • An efficient spatial anti-aliasing method for deferred shading

    Ye Chengchun;Lai Shunnan;Li Sheng;

    In recent years, image-based anti-aliasing techniques have been widely investigated in real-time computer graphics. Compared to traditional routine of anti-aliasing, image-based methods, which combined with deferred shading, can efficiently decouple anti-aliasing step from standard graphics pipeline. However, most of the existing image-based methods consume video memory, bandwidth and computation resources heavily. In this paper, we propose an optimized anti-aliasing method, which can efficiently reduce the multi-sampling rate by a multi-sampling mask. We carefully designed the rendering system to avoid serial execution on branch divergence, by utilizing both modern GPU's features and latest shader model. Experimental results demonstrate that our method can achieve high-quality synthesized image with real-time performance.

    2017年02期 v.27 57-63页 [查看摘要][在线阅读][下载 851K]
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  • Call for Papers

    <正>Introduction Computer Aided Drafting,Design and Manufacturing(CADDM,quarterly)is a international academic journal.It's founded in 1991.CADDM is sponsored by China Graphics Society(CGS),and affiliated to China Association for Science and Technology.Aims and Scopes CADDM aims to serve as a publication and communication platform for researchers in computer image,graphics and visualization.The journal publishes original contributions on computer image,graphics and visualization topics

    2017年02期 v.27 64页 [查看摘要][在线阅读][下载 324K]
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