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Slicing and support structure generation for 3D printing directly on B-rep models

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Visual Computing for Industry,Biomedicine,and Art 2019年第1期2卷 16-25页

作者： Kanle Shi Conghui Cai Zijian Wu junhai yong School of Software Tsinghua UniversityBeijingChina Beijing National Research Center for Information Science and Technology BeijingChina Key Laboratory for Information System Security Ministry of Education of ChinaBeijingChina

Traditional 3D printing is based on stereolithography or standard tessellation language models,which contain many redundant data and have low *** paper proposes a slicing and support structure generation algorithm for 3D printing directly on boundary representation(B-rep)***,surface slicing is performed by efficiently computing the intersection curves between the faces of the B-rep models and each slicing ***,the normals of the B-rep models are used to detect where the support structures should be located and the support structures are *** results show the efficiency and stability of our algorithm.

关键词： 3D printing Boundary representation model Slicing Support structure generation Intersection curve

B-spline surface fitting to mesh vertices

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Science China(Information Sciences) 2017年第7期60卷 259-261页

作者： Yang LU junhai yong Kanle SHI Hejin GU Ping ZHENG Jean-Claude PAUL School of Software Tsinghua University Department of Computer Science and Technology Tsinghua University Key Laboratory for Information System Security Ministry of Education of China Tsinghua National Laboratory for Information Science and Technology Tsinghua University Department of Research & Development Jiangxi Academy of Science Department of Mathematics and Computer Science Nanchang Normal University

Here we propose a novel method of fitting B-spline surfaces to input mesh *** a mesh model that is difficult to fit with one B-spline surface,we divide it into several patches that form a tree structure(which is called hierarchical splines[1]),and for each patch,we use one B-spline surface for ***,only a few patches are required,and G2continuity can be achieved between the adjacent surfaces.

关键词： B-spline surface fitting to mesh vertices

Review of light field technologies

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Visual Computing for Industry,Biomedicine,and Art 2021年第1期4卷 295-307页

作者： Shuyao Zhou Tianqian Zhu Kanle Shi Yazi Li Wen Zheng junhai yong Y-tech Kuaishou TechnologyBeijing 100085China EECS Department University of CaliforniaBerkeleyCA 94720USA School of Software BNRistTsinghua UniversityBeijingChina

Light fields are vector functions that map the geometry of light rays to the corresponding plenoptic *** describe the holographic information of scenes by representing the amount of light flowing in every direction through every point in *** physical concept of light fields was first proposed in 1936,and light fields are becoming increasingly important in the field of computer graphics,especially with the fast growth of computing capacity as well as network *** this article,light field imaging is reviewed from the following aspects with an emphasis on the achievements of the past five years:(1)depth estimation,(2)content editing,(3)image quality,(4)scene reconstruction and view synthesis,and(5)industrial products because the technologies of lights fields also intersect with industrial ***-of-the-art research has focused on light field acquisition,manipulation,and *** addition,the research has extended from the laboratory to *** to these achievements and challenges,in the near future,the applications of light fields could offer more portability,accessibility,compatibility,and ability to visualize the world.

关键词： Light field imaging Holographics Human-machine graphic interaction

Removing local irregularities of triangular meshes with highlight line models

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Science in China(Series F) 2009年第3期52卷 418-430页

作者： yong junhai DENG BaiLin CHENG FuHua WANG Bin WU Kun GU HeJin School of Software Tsinghua University Beijing 100084 China Department of Computer Science and Technology Tsinghua University Beijing 100084 China Department of Computer Science University of Kentucky Lexington KY 40506-0046 USA Key Laboratory for Information System Security Ministry of Education of China Beijing 100084 China Tsinghua National Laboratory for Information Science and Technology Beijing 100084 China jianaxi Academy of Sciences. Nanchang 330029. China

The highlight line model is a powerful tool in assessing the quality of a surface. It increases the flexibility of an interactive design environment. In this paper, a method to generate a highlight line model on an arbitrary triangular mesh is presented. Based on the highlight line model, a technique to remove local shape irregularities of a triangular mesh is then presented. The shape modification is done by solving a minimization problem and performing an iterative procedure. The new technique improves not only the shape quality of the mesh surface, but also the shape of the highlight line model. It provides an intuitive and yet suitable method for locally optimizing the shape of a triangular mesh.

关键词： highlight lines mesh optimization shape modification model repair

A stamp based exploration framework for numerical weather forecast

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Computer Aided Drafting,Design and Manufacturing 2017年第2期27卷 7-15页

作者： Song Yibo Chen Li Liao Hongsen yong junhai School of Software Tsinghua University

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.

关键词： multivariate data visualization numerical weather model ensemble weather forecast

一类五次PH曲线Hermite插值的几何方法

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计算机辅助设计与图形学学报 2005年第5期17卷 990-995页

作者：雍俊海郑文清华大学软件学院北京100084

推导出了五次毕达哥拉斯速端(PythagoreanHodograph ,PH)曲线的B啨ｚｉｅｒ控制点之间的几何关系,给出了构造符合Hermite插值条件的五次PH曲线的几何方法最终的五次PH曲线以B啨ｚｉｅｒ曲线形式给出在此基础上,利用B啨ｚｉｅｒ控制点... 详细信息

推导出了五次毕达哥拉斯速端(PythagoreanHodograph ,PH)曲线的B啨ｚｉｅｒ控制点之间的几何关系,给出了构造符合Hermite插值条件的五次PH曲线的几何方法最终的五次PH曲线以B啨ｚｉｅｒ曲线形式给出在此基础上,利用B啨ｚｉｅｒ控制点对曲线形状性质的影响,分析了符合Hermite插值条件的4条五次PH曲线与相同插值条件下的普通三次B啨ｚｉｅｒ曲线的相似性。

关键词： PH曲线 Hermite插值 Bézier曲线

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一类闭环约束的装配约束问题求解

计算机辅助设计与图形学学报 2008年第9期20卷 1171-1175页

作者：刘勇雍俊海王斌清华大学软件学院

分析了一种可以拆分为等价的开环约束的装配闭环约束问题.给出了等价性的定义,并提出一种该类闭环约束拆分为等价开环约束的方法.首先确定装配几何约束图上的闭环,然后对该闭环利用自由度归约加扰动判定是否从某一条边拆开.该方法能够... 详细信息

分析了一种可以拆分为等价的开环约束的装配闭环约束问题.给出了等价性的定义,并提出一种该类闭环约束拆分为等价开环约束的方法.首先确定装配几何约束图上的闭环,然后对该闭环利用自由度归约加扰动判定是否从某一条边拆开.该方法能够较好的简化CAD软件中用户添加的装配约束,避免了因闭环约束造成的求解复杂度增加的情况,同时可以更好的表达实际装配的过程.

关键词：装配约束求解装配约束推理闭环约束

Automatic wiring method for switchgear design

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Computer Aided Drafting,Design and Manufacturing 2017年第2期27卷 32-38页

作者： Shi Kanle Gao Ying Wu Zijian Zhang Hui yong junhai School of Software Tsinghua University Key Laboratory for Information System Security Ministry of Education of China Tsinghua National Laboratory for Information Science and Technology

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.

关键词： wiring method path searching contour expansion switchgear design A* algorithm

Semantic-driven method for designing 3D busbars

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Computer Aided Drafting,Design and Manufacturing 2017年第2期27卷 16-23页

作者： Shi Kanle Zhu Zixu Wu Zijian Zhang Hui yong junhai School of Software Tsinghua University Key Laboratory for Information System Security Ministry of Education of China Tsinghua National Laboratory for Information Science and Technology

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.

关键词： semantic-driven design busbar design busbar segmentation modeling change of requirement