三维纺织结构增强复合材料的几何模型

基于对织物断面显微照片的观察和分析，首先建立了三维正交织物的单元结构模型，并以此为基础建立了正交接结织物的单元结构模型；利用几何模型公式推导建立几何结构特征参数与编织工艺参数之间的理论关系；在此基础上计算了纱线长度、接结经与经纱的取向角和纤维体积含量；通过几何极限条件定义了织物紧度，为进一步研究其力学性能奠定基础。     

一种基于GPU的大规模地形绘制算法

利用Geometry Clipmap算法的基本思想,对原算法进行简化与改进。在预处理阶段,对地形数据的存储方式进行简化,并采用Clipmap结构进行组织和管理;在绘制阶段,重点针对不同分辨率层次之间的裂缝问题进行分析和处理,提出了一种引入过渡带的方法有效消除了裂缝。实验表明,该方法有效提高渲染速率,并充分发挥GPU的优势,实现了大规模地形数据的实时可视化。     

On The Lower Bound Of Edge Guards Of Polyhedral Terrains

Guarding polyhedral terrains is a relatively new problem in computational geometry. It is known as NP-hard problem. In 1997, P. Bose, T. Shermer, G. Toussaint and B. Zhu stated the bounds on the number of guards and proposed some algorithms for placing vertex and edge guards. In this contribution, we point to the inconsistency in the proof of the lower bound of the number of edge guards. We show that following the approach of Bose et al. for an n-vertex polyhedral terrain only a weaker lower bound of ?(2n?4)/7? can be achieved. Hence deriving the proof for the lower bound equal to ?(4n?4)/13? originally stated by Bose et al. remains an open issue.     

Shape Decomposition using Modal Analysis

We introduce a novel algorithm that decomposes a deformable shape into meaningful parts requiring only a single input pose. Using modal analysis, we are able to identify parts of the shape that tend to move rigidly. We define a deformation energy on the shape, enabling modal analysis to find the typical deformations of the shape. We then find a decomposition of the shape such that the typical deformations can be well approximated with deformation fields that are rigid in each part of the decomposition. We optimize for the best decomposition, which captures how the shape deforms. A hierarchical refinement scheme makes it possible to compute more detailed decompositions for some parts of the shape.
Although our algorithm does not require user intervention, it is possible to control the process by directly changing the deformation energy, or interactively refining the decomposition as necessary. Due to the construction of the energy function and the properties of modal analysis, the computed decompositions are robust to changes in pose as well as meshing, noise, and even imperfections such as small holes in the surface.     

Upgrading Computational Design

Shajay Bhooshan heads up the computation and design ZHACODE group at Zaha Hadid Architects (ZHA) and is a course master at the Architectural Association Design Research Laboratory (AADRL). Here he argues that Parametricism 2.0 has a vital role to play in the progressing of computational design. Assimilating the exploratory developments of the last 15 years, he asserts how the next phase of Parametricism will enable a further consolidation and evolution of digital practices.     

基于空间行为的数字几何空间建造 上海卜石艺术馆改造设计

文章通过介绍卜石艺术馆的改造,探讨了空间行为塑形在建筑设计方法上的应用。指出建筑师在对人的行为过程进行推演和模拟时,形成了几何折叠的空间界面,这种反向生形手法,是一个自下而上的过程,也是在数字性能化设计中所用到的设计逻辑,这种逻辑同时又作为建造方式的指导,给予建筑师实现多维空间创造的可能。     

结构面对岩体爆破块度分布影响的分形探讨

在前人研究成果的基础上，应用分形几何理论探讨了结构面对岩体爆破块度分布影响的分形规律，得出了几点有益的结论．     

几何仿真在数控车削加工过程中的应用

叙述了数控加工中NC代码的传统验证方法及几何仿真的目的和意义,着重讨论了数控车床几何仿真的系统结构以及NC代码验证程序的流程,最后分析了几何仿真中欠切与过切的布尔差算法。通过几何仿真,可以预见机械加工中的许多问题,从而降低设计与制造的成本,提高加工效率。     

三维面模型的几何压缩技术综述

随着应用需求的增长,三维模型的规模和复杂度急剧增长,给模型的存储和在有限带宽的网络上传输带来了很大的困难.因此,研究空间需求小、适合于计算机网络传输的三维模型的表示方法具有十分重要的意义.三维模型的压缩主要包括拓扑压缩和几何压缩.由于压缩数据中的大部分是几何压缩数据,因此已发展了许多几何压缩方法,以提高模型的压缩效率.为使相关的学者和工程技术人员较好地了解几何压缩技术,本文对这方面的工作进行了较全面的介绍.本文首先介绍了几何压缩的基本流程及几种几何压缩方法的分类原则,然后将几何压缩技术分为基础压缩方法和经过模型变换的压缩方法两大类并分别进行详细的介绍,讨论了各个方法的特点,最后结合我们自身的工作认识对几何压缩技术进行小结和展望.