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2.OpenCASCADE
OpenCASCADE code study.
OpenCASCADE教程
OpenCASCADE书籍
OpenCASCADE入门
OpenCASCADE培训
摘要: 本文以OpenCASCADE中简单的二次曲面的轮廓线计算入手来理解曲面的轮廓线概念，为理解任意曲面轮廓线计算打下基础。 阅读全文
摘要: OpenCASCADE的HLR边的分类。 阅读全文
摘要: 本文主要介绍opencascade曲线与曲面求交的实现原理 阅读全文
摘要: 本文主要介绍opencascade二维曲线相交的实现原理。 阅读全文
摘要: 本文主要结合代码介绍OpenCASCADE曲线上点的反求实现原理及使用过程中的一些注意事项。 阅读全文
摘要: 对于拓朴边提供了求交算法IntTools_EdgeEdge，这个类是使用类似于曲面求交的离散网格法，使用了离散包围盒法。 阅读全文
摘要: 学而不思则罔，思而不学则殆。光看书籍的理论知道，没有实践看不到效果。光看occ的源码，没有理论支撑，不能抓住几何问题的本质。 阅读全文
摘要: OpenCASCADE中扫掠造型算法功能还比较强大，除了支持常规的扫掠外，还支持带引导线的扫掠，及带引导线的多个截面的变形扫掠，还支持截面始终垂直于支持面的扫掠选项。扫掠的关键是确定截面的变换规则，底层的蒙皮拟合算法还是比较稳定的。 阅读全文
摘要: 布尔数据中面的相交的结果可能有交线，也可能有交点。将求交结果保存到FaceInfo中。从简单的两个平面重叠来看，将重叠的状态用变量theTangetFaces来保存。那任意两个曲面重叠如何判断呢？面的相交虽然提供类IntTools_FaceFace来计算，但是没有正确处理交线的范围，为什么BOPAlgo_PaveFiller中可以正确处理交线呢？ 阅读全文
摘要: 边与边、边与面相交会得到公共部分Common Part，公共部分可能是点，也可能是重叠的边。在过滤相交的边与边、边与面时都有一定的优化空间，即使用BVH来加速检测相交部分。在快速判断边与边是否重叠、边与面是否重叠部分的代码采用固定数量的采样点的处理方式不太严谨。将相交的结果及过程数据都保存到BOPDS_DS中作为后面算法使用。 阅读全文
摘要: opencascade imgui glfw. 阅读全文
摘要: 布尔数据BOPDS_DS是布尔操作中的数据中转站，将布尔操作的输入数据及中间计算结果数据都保存起来。 阅读全文
摘要: 布尔迭代器BOPDS_Iterator通过BVH找出求交的模型中每对包围盒有相交的模型并提供遍历每对包围盒相交的模型的功能，为后面求交作准备。从其代码实现可以看出布尔选项使用OBB对性能提高是有限的，当使用AABB能检测出来的，再使用OBB会降低性能。当使用AABB检测出来相交，但OBB不相交的场景对性能提升明显。 阅读全文
摘要: opencascade glfw imgui 阅读全文
摘要: 几何内核可以看成一个数学库的子集，只是在几何图形上的应用。学习几何内核的过程类比于学生时代掌握的数学工具。 阅读全文
摘要: OpenCASCADE中对两个曲面求交得到的交线进行了分类: ALine, GLine, WLine, RLine. 阅读全文
摘要: BVH在OpenCASCADE中也有广泛地应用，如开源版本中的模型快速碰撞检测，使用类BRepExtrema_ShapeProximity. 模型选择操作，光线跟踪等算法中都有应用。 阅读全文
摘要: OpenCASCADE中提供一种空间查找二叉树算法NCollection_UBTree，字面意思是非平衡二叉树Unbalanced Binary Tree。把上图中的数字换成包围盒，构造二叉查找树。为了解决查找二叉树单链问题，加入随机处理，可以使查找性能达到O(log(N))，相对普通遍历速度而言还是不错的。本文结合示例代码说明如何使用这个非平衡二叉树。 阅读全文
摘要: 曲面求交追踪法的优点是在求得首交点后搜索交线其余交点的速度非常快，且适用范围广。追踪法的问题是目前尚无非常有效的方法来求得所有交线环的起始点。曲面求交一般会采用通用性较好的网格法-迭代法-追踪法三者相结合的方法。应用网格法求得交点的初始估计值，再用迭代法求得精确交点，并以其为起点进行追踪，直到得到整条精确交线。 阅读全文
摘要: 将曲面求交的离散网格交线作为Newton迭代法的初始估计点，可以得到较好的交线。 阅读全文
摘要: OpenCASCADE中曲面求交的迭代法也不是独立的方法，与之配合的有离散网格求交得到初值，在追踪中作用迭代法。迭代求交使用的是三参数迭代法，根据三参数迭代法的数学方程可知，需要计算曲面上参数对应的点和切矢。 阅读全文
摘要: opencascade使用类IntPolyh_Intersection来计算两个曲面网格的交线。 阅读全文
摘要: OpenCASCADE中计算两个三角网格交线的类是IntPatch_InterferencePolyhedron，这个类还可以用来计算一个网格的自交情况。 阅读全文
摘要: OpenCASCADE曲面求交之网格离散法之曲面离散网格表示。 阅读全文
摘要: 本文主要结合示例代码介绍PlaneGCS的使用方法 阅读全文
摘要: OpenCASCADE-曲面求交 阅读全文
摘要: McCad是一个开源工具，能自动将BRep模型转换成CSG模型。 阅读全文
摘要: OpenCASCADE Visualization Performance
occ的显示模块现在的性能还是很不错的！ 阅读全文
摘要: BRep边界表示法通过对几何曲面加上边界Wire限定得到有界的曲面片后，如何将曲面片连接起来生成一个闭合的Shell，进而得到一个Solid实体？以前写过如何将无序的Edge连接起来生成Wire的方法，今天介绍一下OpenCASCADE中如何将Face连接起来生成Shell。这也是我们要手工通过Vertex, Edge, Face来构造BRep的Solid必须思考和解决的问题。 阅读全文
摘要: PlaneGCS字面意思是平面几何约束求解器，主要用于二维草图。 阅读全文
摘要: occt-7.7.0修复了Mesh问题，提高Mesh速度；
完善2d offset算法，STEP增加网格数据导出； 阅读全文
摘要: 综上所述，几何内核中的数是没有量纲的，可以根据模型的尺度选择合适的单位。OpenCASCADE中BRep体模型最小建模精度为1.e-7。几何数据使用参数方程表示，是精确的数学表示，但是几何算法是有精度的。有些几何算法中有些精度是硬编码的不能修改，这类精度值都要高于1.e-7。有些精度是通过BRep中的拓朴点，边和面传递过来的。为了提高布尔运算的稳定性，引入Fuzzy容差，解决一些接触的容差问题。 阅读全文
摘要: OpenCascade 中的 Thin Plate Spline 插值 阅读全文
摘要: Open Cascade is pleased to announce that the next Open CASCADE Technology (OCCT) maintenance release (version 7.6.3) is prepared.
The sources of Open CASCADE Technology 7.6.3 are available under the V7_6_3 tag in the OCCT repository. 阅读全文
摘要: OpenCASCADE PCurve终极问题 阅读全文
摘要: OpenCASCADE 曲面展开 阅读全文
摘要: OpenCASCADE曲线向曲面投影。 阅读全文
摘要: OpenCASCADE 投影生成PCurve 阅读全文
摘要: OpenCASCADE编码规范-内存对齐 阅读全文
摘要: OpenCASCADE 布尔运算之元件重构BOPAlgo_CellsBuilder 算法。 阅读全文
摘要: OpenCASCADE 布尔运算简介 阅读全文
摘要: OCCT Draw Test Harness中通过命令查找C++源文件方法。 阅读全文
摘要: 点在多边形内  阅读全文
摘要: 通过二次多项式的形式把二次曲线和二次曲面之间的求交问题统一成对将参数方程代入隐式方程得到问题的求解。  阅读全文
摘要: 将无序的EDGE生成WIRE。
阅读全文
摘要: opencascade中对相连曲面圆滑处理的造型算法“滚球法”Rolling Ball介绍。
 阅读全文
摘要: 介绍OpenCASCADE中倒角chamfer的基础概念。
 阅读全文
摘要: OpenCASCADE Chamfer 2D. 二维倒角算法分析。
 阅读全文
摘要: RvmTranslator7.4.0发布啦！主要增加了生成AVEVA PDMS中文的PML宏文件，可以在PDMS中生成三维汉字和其他任意字符。
 阅读全文
摘要: RvmTranslator7.3.2发布啦！主要增加了尺寸测量功能。
 阅读全文
摘要: opencascade pick point. 阅读全文
摘要: STEP AP214的STEP中是带有颜色信息的，OCCT可以读取其中的颜色信息。本文介绍一种比官方XCAFDoc_ColorTool更方便的获取方法。
 阅读全文
摘要: How to Install FreeCAD 0.18 in Ubuntu 18.04 / 16.04. 阅读全文
摘要:  PBR in OCCT 3D Viewer 阅读全文
摘要: BRep_Builder的Add和Remove注意事项。
 阅读全文
摘要: OpenCASCADE自定义高亮效果 阅读全文
摘要: Abstract. Python and C++ are in many ways as different as two languages could be: while C++ is usually compiled to machine-code, Python is interpreted. Python's dynamic type system is often cited as the foundation of its flexibility, while in C++ static typing is the cornerstone of its efficiency. C++ has an intricate and difficult compile-time meta-language, while in Python, practically everything happens at runtime.
Key Words. Qt, Python, Shiboken2, PySide2 阅读全文
摘要: OpenCASCADE动画功能2。 阅读全文
摘要: OpenCASCADE 平面与球面求交源码分析。 阅读全文
摘要: OpenCASCADE中两个平面求交线算法分析。 阅读全文
摘要: opencascade740 beta测试版本发布。 阅读全文
摘要: OpenCASCADE点向圆柱面投影源码分析。 阅读全文
摘要: OpenCASCADE点向直线投影源码分析。 阅读全文
摘要: OpenCASCADE圆与平面求交算法分析。 阅读全文
摘要: OpenCASCADE动画功能介绍。 阅读全文
摘要: OpenCASCADE中计算直线与平面的交点 阅读全文
摘要: 本文主要介绍点向平面投影的注意事项。ProjLib类是个工具类，因为其函数都是静态函数。点向平面投影很简单，直接用ProjLib::Project(aPlane, aPoint)即可。 阅读全文
摘要: 将OpenCASCADE生成VS2008项目来编译 阅读全文
摘要: 1.glTF(GL TransmissionFormat)，即图形语言交换格式，它是一种3D内容的格式标准，由Khronos Group管理（Khronos Group还管理着OpenGL系列、OpenCL等重要的行业标准）；
2.glTF的设计是面向实时渲染应用的，尽量提供可以直接传输给图形API的数据形式，不再需要二次转换；
3.glTF对OpenGL ES、WebGL非常友好；
4.glTF的目标是：3D领域的JPEG；
5.作为一个标准，自2015年10月发布（glTF 1.0）以来，已经得到了业界广泛的认可，你可以相信它的水平；
6.glTF目前最新版本为2.0已于2017年6月正式发布。 阅读全文
摘要: 本文主要结合OpenCASCADE源码分析圆与二次曲面求交的实现，其他二次曲线与二次曲面求交的可以依此类推。 阅读全文
摘要: OpenCASCADE中的包IntAna提供了解析几何曲线（二次曲线）与解析曲面（二次曲面）求交、解析曲面与解析曲面求交的功能。其中IntAna分别是Intersection Analytic的前三个字母缩写，表示解析几何求交。 我们学过了《线性代数》中的二次型，其中二次型在解析几何中的一个应用就是二次曲线和二次曲面方程的化简及其性质的分析。 本文主要结合源码分析直线与二次曲面求解的实现来抛砖引玉，后期将二次曲线与二次曲面求交的各种情况做全面分析。 阅读全文
摘要: 当对OpenCASCADE的BRep表示法的数据结构有了一定的理解后，建议可以自己实现一个显示数据生成的功能，即网格剖分功能。 阅读全文
摘要: OpenCASCADE的网格剖分中网格质量控制是相对重要的核心功能。在理解其原理后，可以自己实现一个更清晰的网格剖分库。
2018年就过结束了，这一年收获颇丰，其中最大的收获就是有了自己的小宝宝。
分享创建价值。虽然OpenCASCADE不是完美的，但是她是目前世界上唯一一款功能相对完善的开放的几何造型库。OpenCASCADE的开放分享，给她带来生机。当他人因为我的blog的分享的文章或代码联系我时，他们的一声感谢，我都会觉得很高兴。
2019年马上就要到来，希望大家在新的一年里，创造、创新，突破自我，更上一层楼！ 阅读全文
摘要: I am pleased to announce a new release of RvmTranslator6.6.
RvmTranslator6.6主要增加导出带设计结构的STEP文件，此文件在导入CATIA后的结构与模型与PDMS中一致. 阅读全文
摘要: 管道标准部件库程序PipeStd的主要用法与PDMS的Paragon模块类似，主要也是采用参数化的方式来表示管件。每种类型的管件Category包含三个集合：参数集Parameter Set、点集Point Set和形集Geometry Set。本文主要来介绍如何创建一个参数化的标准管件。 阅读全文
摘要: PipeCAD之管道标准库PipeStd，来对管件及管道等级Piping Specification数据进行管理。 阅读全文
摘要: 要显示一个逼真的三维模型，其顶点坐标、顶点法向、纹理坐标这三个信息必不可少。本文主要介绍如何在OpenCASCADE的Draw中显示出曲面的法向量，通过使用相关命令，来方便地对曲面的法向进行检查。 阅读全文
摘要: 在OpenCASCADE中基于BRepBuilderAPI_MakeFace直接生成的带孔的面，还可以进一步使用放样算法来造型，如拉伸，旋转等，如下图所示。这样就可以避免使用布尔操作，提高造型算法的性能和稳定性。 阅读全文
摘要: RvmTranslator6.5发布。
这个版本主要修复转换3DXML的相关Bugs. 阅读全文
摘要: 整个Qt在Windows中都可以通过批处理来编译，当编译好Qt后，会生成qmake.exe。 在没有安装Qt-VS-Addin的情况下，如何使用别人提供的Qt *.pro项目文件呢？ 使用qmake可以直接生成Visual Studio项目文件 阅读全文
摘要: Gauss-Newton算法是一个古老的处理非线性最小二乘问题的方法。该方法在迭代过程中要求矩阵J(x)满秩。为了克服这个困难，Levenberg(1944)提出了一种新的方法，但未受到重视。后来Marquardt(1963)又重新提出，并在理论上进行了控讨，得到Levenberg-Marquardt方法，简称LM方法。在此基础上，Fletcher(1971)对其实现策略进行了改进，得到了Levenberg-Marquardt-Fletcher方法（LMF）。再后来，More(1978)将LM方法与信赖域方法结合，建立了带信赖域的LM方法。 LM算法的产生主要是解决曲线最小二乘拟合问题，现在很多软件使用LM算法来解决通用的曲线拟合问题。 本文主要介绍GPL开源库levmar2.6使用Visual Studio在Windows上进行编译。 阅读全文
摘要: 在科学技术领域里常常提出求解非线性方程组的问题，例如，用非线性函数拟合实验数据问题、非线性网络问题、几何上的曲线曲面求交问题等。OpenCASCADE中有关于非线性方程组定义的类及其求解类，本文主要介绍如何在OpenCASCADE中定义非线性方程组，及对其进行求解。 阅读全文
摘要: RvmTranslator6.4版本发布，修改了部分模型丢失的问题。 阅读全文
摘要: Intel TBB并行计算库更改许可为Apache V2.0，使用更加自由。 不过TBB 2017版本之前的版本还是GPL许可，之后版本才是Apache V2.0许可。所以如果想在基于opencascade开发的软件中使用TBB而不用开源自己的代码的话，可以使用TBB 2017之后的版本。 阅读全文
摘要: OpenCASCADE扩展的数据交换模块XDE(Extended Data Exchange)可以转换附加在几何BREP体中其他信息，如颜色、图层，装配结构等，因此提高与其他CAD软件的兼容性。目前包含这些信息的文件格式有IGES和STEP。 阅读全文
摘要: RvmTranslator can translate the RVM file exported by AVEVA Plant(PDMS)/AVEVA Marine to STEP, IGES, STL, DXF, 3D PDF, OBJ, 3DXML, .etc. So it can be used for exchanging model data between other CAD software, such as Autodesk AutoCAD, Plant3d, 3ds Max, CATIA, Solidworks, Pro/E, Unity3d, .etc. I am pleased to announce a new release of RvmTranslator6.2. 阅读全文
摘要: 中南设计集团（武汉）工程技术研究院有限公司招聘图形算法工程师。
工作职责：
从事BIM平台中图形及几何算法相关研究和开发工作；
任职要求：
1、本科及以上学历，有较强的学习和适应能力
2、2~3年以上工作经验，建筑、机械、数学、计算机等相关专业；
3、熟练掌握C++及Python脚本语言，具有深厚的算法设计基础，数学功底好；
4、熟悉计算几何及图形学算法，OpenCASCADE库及OSG图形引擎；
5、具有三维CAD和建筑设计类软件研发经验者优先考虑. 阅读全文
摘要: OpenCASCADE7.3.0发布了，与7.2.0版本相比包含了350个新的功能还有很多bug的修复。
OpenCASCADE7.3.0下载。 阅读全文
摘要: 在OpenCASCADE中生成WIRE时要求添加到WIRE中的边EDGE是有顺序要求的。当给定的边没有按顺序添加到WIRE之前，需要自己将EDGE按顺序处理。OpenCASCADE中也提供了对EDGE按顺序进行排序的功能，方便WIRE的生成。
本文给出将散乱的EDGE排序后生成WIRE的实现代码，这个功能用处还是很大的。 阅读全文
摘要: OpenCASCADE提供了基于BREP体的Boolean Operations，但是如果Topo体中只包含三角网格信息的话，是不支持布尔运算的。典型的例子就是由STL导入生成的模型在OpenCASCADE中是不能进行布尔运算。
有一些开源库提供了基于三角网格的布尔运算的功能。如MeshLab、Cork等。本文主要就来介绍一下这两个库中的基于三角网格的布尔运算功能。 阅读全文
摘要: We present an overview of current real-time massive model visualization technology, with the goal of providing readers with a high level understanding of the domain, as well as with pointers to the literature.
本文展示了当前大规模模型实时可视化技术的概况，目的是为了给读者们对这个领域一个比较深入的认识，并指出学术界的一些研究的文献。 阅读全文
摘要: Abstract. 纹理贴图技术的出现和流行是图形显示技术的一个非常重要的里程碑，直接影响3D技术从工业进入娱乐领域。本文结合OpenCASCADE中纹理贴图的源码，来说明纹理贴图在OpenCASCADE中实现。
Key Words. OpenCASCADE 纹理贴图, Texture Mapping 阅读全文
摘要: RvmTranslator6.1 add the attribute list for the tree node. If there is a *.att file in the same folder of the *.rvm file, the attribute list will show them for the selected tree node. 阅读全文
摘要: Major companies from the manufacturing industry (aerospace, ground transportation, industrial machinery) use IC.IDO VR software to perform collaborative and immersive design reviews, to evaluate and optimize assembly and disassembly sequences, to verify resources and tooling for both manufacture and maintenance, to support documentation and workflow animation/ training. IC.IDO detects contact and obstruction during assembly and maintenance procedures, and enables instant evaluation of flexible c 阅读全文
摘要: Abstract. Sweeps are the objects you obtain by sweeping a profile along a path. Sweep is a very useful modeling algorithm. The paper focus on the introduction of the sweep algorithms in the opencascade.
Key Words. Sweep, Prism, Revol, Pipe, Frenet Trihedron, 阅读全文
摘要: 曲线的活动标架是《微分几何》中一个很基础的概念。有了曲线的活动标架，扫掠造型Sweep算法的实现有了一些思路。当给定一个轮廓线后，将轮廓线沿着路径曲线扫掠可以理解为将轮廓线变换到曲线的活动标架中。 本文主要演示了Frenet活动标架的例子，读者可以将GeomFill_TrihedronLaw其他的子类表示的其他类型活动标架自己实现，加深理解。 阅读全文
摘要: 在OpenCASCADE的TKGeomAlgo Toolkit中提供了一个Law Package，在Law包中有一个基类：Law_Function，字面上翻译为 规则函数。 本文主要对Law_Function的子类进行介绍，进一步理解OpenCASCADE中Law相关类的作用。 阅读全文
摘要: Abstract. OpenCASCADE ActiveX wrapper for VB, C#, Web, Delphi.
Key Words. OpenCASCADE, ActiveX, VB, Delphi, C#, Web 阅读全文
摘要: Abstract. A ruled surface is formed by moving a line connecting points of equal relative arc length or equal relative parametric value on two parametric curves from a start point to a terminate point on the curves. The paper focus on the ruled surface in opencascade.
Key words. OpenCascade, Ruled Surface, 直纹面 阅读全文
摘要: Abstract. 本文主要介绍常见的曲面如一般柱面（拉伸曲面）、旋转面在OpenCASCADE中的构造方法，由此思考一般放样算法的实现。
Key Words. Common Surface, Extrusion, Revolution 阅读全文
摘要: OpenCASCADE 公众号
今天也注册了一个微信公众号，以后会在微信公众号中发表OpenCASCADE学习文章，Blog会与微信公众号同步。下面是微信公众号二维码，欢迎大家关注交流OpenCASCADE. 阅读全文
摘要: 管子零件图、管子小票图材料列表生成及件号标注。 阅读全文
摘要: 船舶管子零件图,PipeSketches 阅读全文
摘要: Abstract. 本文介绍了参数曲面的第一基本公式，并应用曲面的第一基本公式，结合OpenCASCADE中计算多重积分的类，对任意参数曲面的面积进行计算。
Key Words. Parametric Curve, Parametric Surface, Gauss Integration, Global Properties 阅读全文
摘要: Abstract. OpenCASCADE package BRepMesh can compute the Delaunay’s triangulation with the algorithm of Watson. It can be used for 2d plane or on surface by meshing in UV parametric space. The blog focus on the usage of the triangulation tool to triangulate 2d points.
Key Words. BRepMesh, Delaunay Triangulation, 阅读全文
摘要: Abstract. 管道设计CAD系统中都有涉及到重量重心计算的功能，这个功能得到的重心数据主要用于托盘式造船时方便根据重心设置吊装配件。重量信息主要用于采购订货。本文主要介绍相关软件中重量重心功能，及重量重心计算实现原理。最后结合OpenCASCADE计算管道模型重量重心来验证。
Key Words. CoG, CentreOfMass, Piping CAD, Piping Design 阅读全文
摘要: Abstract. IsoAlgo3d 通过将PCF三维可视化，并导出HTML文件。由于使用WebGL技术，所以只要设备支持HTML5，就可以不用安装任何软件或插件直接浏览PCF对应的全尺寸标注的管道三维模型，不管是电脑、平板还是智能手机。三维直接浏览管道模型，更加直观，避免了二维ISO图有时表达不清晰的情况，如环管出图，复杂管线分图后识图困难等，方便现场施工。
Key Words. IsoAlgo3d, 管道ISO图，三维管道图，WebGL, 平板，手机 阅读全文
摘要: Abstract. FreeType is required for text display in the 3D viewer. FreeType is a software font engine that is designed to be small, efficient, highly customizable, and portable while capable of producing high-quality output(glyph images). It can be used in graphics libraries, display servers, font conversion tools, text image generation tools, and many other products as well. The blog is focus on the FreeType usage in OpenCASCADE to convert text to BRep shape.
Key Words. FreeType, OpenCA 阅读全文
摘要: Abstract. OpenCASCADE provides a simple twist drill bit modeling example in Tcl script. The blog will give a details of some key points, when you understand the key points, you can modeling the shape like that.
Key Words. OpenCASCADE, Twist Drill Bit Modeling, Tcl 阅读全文
摘要: OpenCASCADE各版本源码下载 阅读全文
摘要: Abstract. Sometimes you want to split a shape by plane or even split a shape by a B Spline surface, OpenCASCADE provide a feature class BRepFeat_SplitShape to implement the function. The paper give a sample code to split a cylinder by plane.
Key Words. Split Shape, BRep Feature Algorithms. 阅读全文
摘要: Trackball, Quaternion, View Transform 阅读全文
摘要: 本系统的电梯模型模拟三层楼，当轿厢系统上升（下降），重量平衡系统下降（上升），顶部的曳引系统则类似一个轮轴，要不停的旋转顺时针（逆时针），当电梯到达指定楼层时，轿厢的门能开关。因此现阶段的动画要求是实现轿厢系统上下运动、重量平衡系统上下运动、曳引机的旋转和轿厢门的开关动画。 阅读全文
摘要: Abstract. Bounding Volume Hierarchy(BVH) organizes geometric objects in the tree based on spatial relationships. Each node in the tree contains an axis-aligned bounding box of all the objects below it. Bounding volume hierarchies are used in many algorithms to support efficient operations on the sets of geometric objects, such as collision detection, ray-tracing, searching of nearest objects, and view frustum culling. The paper focus on the usage of BVH on TopoDS_Shape, and its application.
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摘要: SdnfViewer - 3D Viewer for SDNF File.
Use SdnfViewer to view the structure model by SDNF file. The SdnfViewer is under developing, if you have any questions, suggestions, you can send me email, my email address is: eryar@163.com. 阅读全文
摘要: Abstract. Starting from OCCT6.8.0 will include one more algorithm for solving global optimization problems. Its development has been triggered by insufficient performance and robustness of existing algorithm of minimization of curve-surface distance in Extrema package. The PSO, Algorithms in this family are stochastic, and this feature can be perceived as opposite to robustness. However, we found it was not only much faster than original deterministic one, but also more robust in complex real-wo 阅读全文
摘要: Abstract. OpenCASCADE provides the algorithm to implement of the intersection between two 2d conic curve. The conic is defined by its implicit quadaratic equation, so the intersection problem is become a polynomial roots finding problem. The paper focus on the two conic curve intersection algorithm implementation.
Key Words. 2d conic intersection, conic equation 阅读全文
摘要: Abstract. OpenCASCADE provides the algorithm to implementation of the analytical intersection between a 2d line and another conic curve. The conic is defined by its implicit quadaratic equation, so the intersection problem is become a polynomial roots finding problem. The paper focus on the 2d line intersection another conic algorithm implementation.
Key Words. 2d line intersection, conic 阅读全文
摘要: Abstract. OpenCASCADE provides the algorithm to search the intersection point between 3 planes. If two of the planes are parallel or identical, will get no result.
Key Words. Plane Intersection 阅读全文
摘要: Abstract. OpenCASCADE geometric tools provide algorithms to calculate the intersection of two 2d curves, surfaces, or a 3d curve and a surface. Those are the basis of the Boolean Operation, so under the implementation can help to under the BO algorithms. The paper focus on the intersection of two 2d analytical line.
Key Words. OpenCASCADE, Line Intersection 阅读全文
摘要: In Visual Studio you can specify changes to environment variables in the project settings. Open your project, go to Project -> Properties... Under Configuration Properties -> Debugging, edit the Environment value to set environment variables.
For example, if you want to add the directory “c:\foo\bin” to the path when debugging your application, set the Environment value to “PATH=%PATH%;c:\foo\bin”.
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摘要: RvmTranslator6.0 Preview:
1.Introduce Qt for a good GUI;
2.Support Dassault Systemes 3DXML translation; 阅读全文
摘要: Abstract. EasyMesh is developed by Bojan Niceno, it is a two-dimensional quality mesh generator. EasyMesh can generate two dimensional, unstructured, Delaunay and constrained Delaunay triangulations in general domains. It can handle holes in the domain. The paper focus on the usage of EasyMesh.
Key Words. EasyMesh, Delaunay Triangualtion, Triangulation, Mesh 阅读全文
摘要: 上海地目信息科技有限公司招聘OpenCASCADE相关图形开发人员，有兴趣的可直接与hr联系。 阅读全文
摘要: Abstract. OpenCASCADE7.1.0 introduces new built-in interactive object AIS_Manipulator providing interface for moving objects within 3D viewer. The class features three kinds of transformation modes for attached objects: translation through axis, scaling within axis, rotation around axis. The object can be activated using vmanipulator command within Draw Test Harness.
Key Words. OpenCASCADE, 3D Viewer Interactive, Model Editor, Manipulator 阅读全文
摘要: Abstract. The paper based on OpenCASCADE algorithms to approximate the NURBS curve to arc spline. The method is most useful in numerical control to drive the cutter along straight line or circular paths. Or in the shipbuilding industry to manufacture section bar for cold frame bender.
Key Words. NURBS, Biarc approximation, arc spline, 阅读全文
摘要: Abstract. Qt’s ActiveX and COM support allows Qt for Windows developers to access and use ActiveX controls and COM objects provided by any ActiveX server in their Qt applications. Make their Qt application available as COM servers, with any number of Qt objects and widgets as COM objects and ActiveX controls. Make OpenSceneGraph to ActiveX controls then you can use it in other place, like IE.
Key Words. OpenSceneGraph, ActiveX, COM, ActiveQt 阅读全文
摘要: Abstract. The TopLoc package of OpenCASCADE gives resources to handle 3D local coordinate systems called Locations. A Location is a composition of elementary coordinate systems, each one is called a Datum. The Location keeps track of this composition. The paper will use the Draw Test Harness to illustrate the Location concept.
Key Words. Transformation, Location, Local Coordinate Systems 阅读全文
摘要: OpenCASCADE BRepProj_Projection 阅读全文
摘要: 对于几何造型内核OpenCASCADE，由于会涉及到大量的数值算法，如矩阵相关计算，微积分，Newton迭代法解方程，以及非线性优化的一些算法，如BFGS，FRPR，PSO等等用于多元函数的极值求解，所以这些数值算法的性能直接影响系统的性能。软件的性能优化是计算机软件开发过程中需要一直关注的重要因素，因此有必要学习下C++应用程序性能优化的方法。 阅读全文
摘要: IsoAlgo3d is a PCF format 3d visualization tool. I publish it on github to open the source code. Its license is GPL, you can use the IsoAlgo3d freely.
https://github.com/eryar/IsoAlgo3d
You can download the source code and contribute your modification.
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摘要: PCurve is a powerful modeling method, to make helix shapes in occQt to help you understand pcurve better, then you can also can model some intereting shape based on pcurve.
OpenCASCADE does not provide helix curve directly, but you can build a helix curve by the pcurve of a surface(curve on surface). When you understand the pcurve of a surface, you can make a helix curve easily.
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摘要: Abstract. OpenCASCADE provide data structure of any expression, relation or function used in mathematics. Flex and Bison are tools for building programs that handle structured input. They were originally tools for building compilers, but they have proven to be useful in many other areas. The Expression Interpreter in OpenCASCADE is made by Flex and Bison. So let’s know something about Flex and Bison.
Key Words. OpenCASCADE, Expression Interpreter, Flex, Bison 阅读全文
摘要: FreeCAD是一个参数化的三维造型软件，主要用于任意大小的实际模型的设计。参数化的建模方式可以通过修改相关参数从而方便地修改你的设计。FreeCAD是开源软件，并提供了便利地自定义方式，也提供了脚本，从而根据自己的需要去扩展功能。FreeCAD是跨平台（Windows, Mac和Linux），可以读写许多开放的模型文件，如STEP，IGES，STL，SVG，DXF，OBJ，IFC，DAE等。
如果说学习OpenCASCADE可以了解一些几何内核底层的算法，那么学习FreeCAD则可以用来实现一些具体的功能，从而将三维的技术应用到实际的生活中去，创造出有意义的功能。
本文详细说明如何在Windows平台上编译FreeCAD源码。如果你已经可以正常编译OpenCASCADE这种开源库的源码，那么编译FreeCAD还是很简单的。 阅读全文
摘要: Abstract. Today most 3D engineering model data are save to 3D PDF files. Universal 3D(U3D) along side Product Representation Compact(PRC), U3D is the historical foundation used to embed 3D interactive data and models into a PDF file. But PRC is now the preferred and most feature-rich method to embed 3D data into a PDF file. So the paper is focus on to translate OpenCASCADE geometry data to 3D PDF by embedding PRC file.
Key Words. PDF 3D, OpenCASCADE, U3D, PRC, libharu 阅读全文
摘要: Abstract. In modeling, it is often required to approximate or interpolate points to curves and surfaces. In interpolation, the process is complete when the curve or surface passes through all the points; in approximation, when it is as close to these points as possible. The paper is the translation of the OpenCASCADE Modeling Data user guide.
Key Words. Interpolation, Approximation, Fitting 阅读全文
摘要: PDMS数据交换, RvmTranslator 阅读全文
摘要: Abstract. The general method to directly create an edge is to give a 3D curve as the support(geometric domain) of the edge. The curve maybe defined as a 2D curve in the parametric space of a surface: PCurve. When you understand the pcurve, you can modeling some interesting shapes, such as bottle neck thread, helix spring, ring type spring. Etc. The paper is focus on the Ring Type Spring Modeling in OpenCASCADE Draw Test Harness by Tcl script.
Key Words. Spring, Helix, Tcl/Tk, 环形弹簧 阅读全文
摘要: OpenCascade Jobs
OpenCascade相关工作信息发布。 阅读全文
摘要: 为了帮助OPEN CASCADE新手顺利编译OPEN CASCADE源码，特录制了一个视频，
有了这个视频，OPEN CASCADE的编译再也不麻烦啦！ 阅读全文
摘要: Abstract. The common math algorithms library provides a C++ implementation of the most frequently used mathematical algorithms. These include: algorithms to solve a set of linear algebraic equations, algorithms to find the minimum of a function of one or more independent variables, algorithms to find roots of one, or of a set of non-linear equations, algorithm to find the eigenvalues and eigenvectors of a square matrix. The solver for function set is used widely in extrema value evaluation, poin 阅读全文
摘要: Abstract. In calculus, Newton’s method is used for finding the roots of a function. In optimization, Newton’s method is applied to find the roots of the derivative. OPEN CASCADE implement Newton method to find the extrema for a multiple variables function, such as find the extrema point for a curve and a surface.
Key Words. Nonlinear Programming, Newton Method, Extrema, OPEN CASCADE 阅读全文
摘要: Abstract. Multiple variable function with gradient and Hessian matrix is very very import in OPEN CASCADE optimization algorithms. In order to understand these optimization algorithm better, let’s study some basic knowledge about Gradient, Hessian Matrix.
Key Words. Multiple Variable Function, Gradient, Hessian Matrix, 最优化算法, 阅读全文
摘要: Abstract. The least square can be used to solve a set of n linear equations of m unknowns(n >= m). The OPEN CASCADE class math_GaussLeastSquare implements the least square solution of the linear equations by using Gauss LU decomposition algorithm. The paper focus on the Least Square method to solve the linear equations.
Key Words. Least Square, LU Decomposition, Linear Equations 阅读全文
摘要: Abstract. 设计一条复杂曲线时，出于设计和制造上的考虑，常常通过多段曲线组合而成，这就需要解决曲线段之间如何实现光滑连接的问题。评价曲线间连接的光滑度的度量有两种：参数连接性和几何连续性。本文对这两种连续性分别进行介绍。
Key Words. Curve Continuity, Geometric Continuity, 参数连续性、几何连续性 阅读全文
摘要: Abstract. Global curve interpolation to point data is a way to construct curves. The paper focus on the interpolate algorithm in OPEN CASCADE, and give a simple example to demonstrate the usage of the GeomAPI_Interpolate class.
Key Words. Interpolate, NURBS, BSpline, OPEN CASCADE 阅读全文
摘要: Abstract. Clash detection is used for the model collision check. The paper introduce the clash detection in PDMS, and also about how to set the piping component for the operation space clash check.
Key Word. Clash Detection, Collision Detection
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摘要: Abstract. Power basis polynomial is the most simple polynomial function. It also be called power series. OpenCASCADE provides basic computation functions for polynomial functions, such as evaluate the result for a given polynomial, Lagrange interpolation, Hermite interpolation, .etc. The package named PLib, means Polynomial functions Library. The paper focus on the Lagrange interpolation usage of PLib.
Key Words. OpenCASCADE, PLib, Interpolation, Lagrange, 插值 阅读全文
摘要: RvmTranslator2.1 [20150818]
----------------
1. Improve performance for STEP translation;
2. Finish parse all the primitive shapes in RVM file; 阅读全文
摘要: Abstract. As implementation of one of the strategic steps in OpenCASCADE visualization component development road-map, support for GLSL shader programs has been added in OpenCASCADE Technology 6.7.0.
Key Words. OpenCASCADE, GLSL, Shader, Gooch Shader 阅读全文
摘要: Abstract. The OpenGL Shading Language syntax comes from the C family of programming languages. Tokes, identifiers, semicolons, nesting with curly braces, control-flow, and many key words look like C. GLSL provides three qualifiers which form the interfaces of the shaders to their outside world.
Key Words. OpenGL, GLSL, Qualifiers, 阅读全文
摘要: Abstract. OpenCASCADE does not provide helix curve directly, but you can build a helix curve by the pcurve of a surface(curve on surface). When you understand the pcurve of a surface, you can make a helix curve easily. The paper first make a helix by Tcl in Draw Test Harness, then translate the Tcl script to OpenCASCADE C++ code.
Key Words. OpenCASCADE, Helix Curve, PCurve, Sweep, Spring 阅读全文
摘要: Abstract. OpenGL Shading Language, the high-level programming language defined to allow application writers to write programs that execute on the programmable processors defined within OpenGL. Informally the language is sometimes referred to as GLSL. The GLSL has been made part of the OpenGL standard as of OpenGL2.0. The paper focus on a simple example of OpenGL Shader, which can be used as a guide of GLSL.
Key Words. OpenGL, OpenGL Shading Language, GLSL, Shader, Qt 阅读全文
摘要: It can compile and run correctly, the compile error in occQt do not appear in the test program. you can also debug the code in Qt Creator. So use Qt Creator to program on Linux is very convenient. 阅读全文
摘要: AVEVA的RVM文件格式包含了三维模型数据及其他信息，可用于工厂模型的浏览、评审等。常见的三维浏览及评审软件如Autodesk的Navisworks、Intergraph的评审软件SmartPlant Review Publisher等，都提供了对RVM格式的支持。 阅读全文
摘要: Abstract. OpenCASCADE provides a class BRepBuilderAPI_MakeFace to build topological faces. A face maybe built from a surface, elementary surface from gp package, surface from Geom, from a wire and find the surface automatically if possible, etc. If a face is built, how to check it for visualization? What does PCurve means? The paper will answer those question.
Key Words. OpenCASCADE, Topological Face, PCurve, Holes 阅读全文
摘要: Abstract. AVEVA Review is used for 3D model visualisation for plant or ship design, construction and operation. The RVM file is main input of AVEVA Review. RvmTranslator can translate RVM file to STEP, IGES, STL, etc without Review, only rely on the RVM file.
Key Words. AVEVA Review, PDMS RVM, STEP, IGES, STL, Data Exchange 阅读全文
摘要: Abstract. OpenCASCADE BRepTools provides utilities for BRep data structure. OuterWire method to find the outer wire of a face. Dump method to dump a BRep object. It also can be used as the data exchange for OpenCASCADE native shapes.
Key Words. OpenCASCADE, BRepTools, BRep, Topology 阅读全文
摘要: 在管道设计过程中，会使用到大量的标准，如ASME，DIN，GB，CB，HG，SH等等。管道设计人员在设计过程中，需要翻阅相关标准手册，查找所需要的数据，较为繁琐。如果能将相关管件的数据以直观的方式展示出来，可以极大地提高管道设计人员的设计效率。
pipedata3d通过把标准数据以表格及三维模型的方式展示出来，更加形象直观，在方便设计人员查询数据的同时，增加了些许趣味性，提高设计效率。
pipedata3d操作简单，且可客户定制标准数据，扩展方便，有以下特点：
三维模型显示部件及尺寸标注，非常直观；
标准数据扩展方便，使用Tcl脚本实现；
标准数据将会放在网上共享； 阅读全文
摘要: Abstract. Pipedata3d show piping component data in tables and 3D modeling. It can help the piping designers to looking up piping information quickly and so improve the efficiency of piping design.
Key Words. Pipedata3d, ASME, GB, HG, CB, Piping Design 阅读全文
摘要: Abstract. The Visual Studio Natvis framework lets you customize the way Visual Studio displays native types in debugger variable windows such as the Watch, Locals and Data Tips windows. It supersedes the autoexp.dat file that has been used in earlier versions of Visual Studio and offers XML syntax, better diagnostics, versioning, and multiple file support. The container in OpenCASCADE is difficult for debugging, such as TColStd_Array1OfInteger in the TColStd package, .etc. Use the natvis framewo 阅读全文
摘要: Abstract. Qt contains a set of item view classes that use a model/view architecture to manage the relationship between data and the way it is presented to the user. The separation of functionality introduced by this architecture gives developers greater flexibility to customize the presentation of items, and provides a standard model interface to allow a wide range of data sources to be used with existing item views. Model 3D aided design software such as AVEVA Plant/PDMS, Marine use the archite 阅读全文
摘要: Abstract. OpenCASCADE provides a general transformation class: gp_GTrsf. It can be a transformation from gp, an affinity, or you can define your own transformation giving the matrix of transformation. The general transformation contains the vectorial part of the transformation and the translation part. A GTrsf transformation is only applicable to coordinates. Be careful if you apply such a transformation to all points of a geometric object, as this can change the nature of the object and thus re 阅读全文
摘要: Abstract. Tcl/Tk provide a programming system for developing and using graphical user interface(GUI) applications. Tcl stands for “tool command language” and is pronounced “tickle”, is a simple scripting language for controlling the extending applications. The blog use Tcl/Tk to iterate all the files for a given directory, this is useful to some automation work, such as change all the file names for a given directory; add copyright info for the source code files.
Key Words. Tcl/Tk, Iter 阅读全文
摘要: Abstract. Qt’s Undo Framework is an implementation of the Command Pattern, for implementing undo/redo functionality in applications. The Command pattern is based on the idea that all editing in an application is done by creating instances of command objects. Command objects apply changes to the document and are stored on a command stack. Furthermore, each command knows how to undo its changes to bring the document back to its previous state. As long as the application only uses command objects t 阅读全文
摘要: Abstract. To provide the precision required in industrial design, drawings need to offer the possibility of removing lines, which are hidden in a given projection. OpenCASCADE provides two algorithms for this Hidden Line Removal component. The paper mainly translate the document of OpenCASCADE Modeling Algorithms, and give some applications in the plant design CAD software.
Key Words. OpenCASCADE, HLR, Hidden Line Removal 阅读全文
摘要: Abstract. OpenCASCADE have provided the Qt samples in the samples directory, but they are a little complicated. So I decide write a simple OpenCASCADE Qt demo for the OpenCASCADE beginners.
Key Words. OpenCASCADE6.8.0, Qt5.4 阅读全文
摘要: Abstract. Siemens’ JT data format accepted as the world’s first ISO international standard for viewing and sharing lightweight 3D product information. OpenCASCADE JT Assistant is a viewer for files in JT format.
Key Words. Simens JT, JtOpen, OpenCASCADE, Jt Assistant 阅读全文
摘要: Abstract. When you finish modeling objects in the scene, you must want to use some operations to view the scene objects, such as Pan, Zoom and Rotate the scene. Pan and Zoom is easy to understand, rotate the 3D scene according to 2D point in the viewport is a little complicated. There are many methods to rotate the 3D scene, but the Arcball Controller is intuitive for the user and any viewport can be described. You can rotate your model at will just by using the mouse.
Key Words. OpenCA 阅读全文
摘要: OpenCASCADE使用Doxygen及一些第三方程序来自动生成文档，简化程序开发过程中的文档工作。尤其是Tcl/Tk脚本的使用，让重复机械的劳动由电脑来自动完成，提高工作效率及编程的乐趣。
如果想使用搜索功能，可以自己运行gendoc.bat并指定搜索模式为local即可解决问题。 阅读全文
摘要: Abstract. The purpose of the OpenGL graphics processing pipeline is to convert 3D descriptions of objects into a 2D image that can be displayed. In many ways, this process is similar to using a camera to convert a real-world scene into a 2D print. To accomplish the transformation from 3D to 2D, OpenGL defines several coordinate spaces and transformations between those spaces. Each coordinate space has some properties that make it useful for some part of the rendering process. The transformations 阅读全文
摘要: Abstract. OpenCASCADE introduce a new class Graphic3d_Camera for the Visualization module. The camera class provides object-oriented approach to setting up projection and orientation properties of 3D view. The paper use GLUT to test the function of the new Camera class.
Key Words. OpenCASCADE, Camera, OpenGL, GLUT, Transformations 阅读全文
摘要: Abstract. The quaternions are members of a noncommutative division algebra first invented by William Rowan Hamilton. The idea for quaternions occurred to him while he was walking along the Royal Cannal on his way to a meeting of the Irish Academy, and Hamilton was so pleased with his discovery that he scratched the fundamental formula of quaternion algebra. There are several different ways we can express orientation and angular displacement in 3D. Here we discuss the three most important methods 阅读全文
摘要: OpenGL Shader Test - Shadertoy 阅读全文
摘要: Abstract. OpenCASCADE linear extrusion surface is a generalized cylinder. Such a surface is obtained by sweeping a curve (called the “extruded curve” or “basis”) in a given direction (referred to as the direction of extrusion and defined by a unit vector). The u parameter is along the extruded curve. The v parameter is along the direction of extrusion. The form of a surface of linear extrusion is generally a ruled surface. It can be a cylindrical surface, or a planar surface.
Key Words. 阅读全文
摘要: Abstract. The sphere is the simplest topology shape of the BRep structure. But there are several import concept of the sphere edges, such as degenerated edge and seam edge. So construct a sphere by code, you will learn these.
Key Words. OpenCASCADE, Sphere, BRep 阅读全文
摘要: Abstract. By making a simple box to demonstrate the BRep data structure of the OpenCASCADE. The construction method is different from BRepPrimAPI_MakeBox. In the paper construct the box from vertex, edge to solid, while in BRepPrimAPI_MakeBox from solid, shell to vertex. From the construction, the BRep data structure in OpenCASCADE also can be called the Winged-Edge data structure.
Key Words. OpenCASCADE, BRep, Box, The Winged-Edge Structure 阅读全文
摘要: OpenCASCADE Code Study Outline.
OpenCASCADE Collaborative development portal
Updating……
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摘要: Abstract. BRep short for Boundary Representation. First give the definition of the BRep, then compare the BRep mode between OpenCASCADE and OpenNURBS. There are 3 main representation method: use face/edge/vertex to keep track all information in the solid model. The winged-edge data structure uses edges to keep track all information in the solid model. The paper focus on the BRep of OpenCASCADE and OpenNURBS.
Key Words. OpenCASCADE, BRep, OpenNURBS, The Winged-edge Structure, 阅读全文
摘要: Abstract. The openNURBS Toolkit consists of C++ source code for a library that will read and write a openNURBS 3D model file(.3dm). More than 400 software development teams and applications including Rhinoceros, exchange 3-D models using the openNURBS (.3dm) file format. But there is no a simple viwer for 3dm on PC except Rhinoceros. So I want to develop a 3DM viewer based on OpenSceneGraph to visualize the 3DM file.
Key Words. OpenNURBS, 3DM Viewer, OpenSceneGraph 阅读全文
摘要: Abstract. The OpenNURBS initiative provides CAD/CAM/CAE and computer graphics software developers the tools to accurately transfer 3D geometry between applications. The OpenNURBS C++ source code is clean and fairly simple. The OpenNURBS Toolkit is intended for use by C++ and .NET programmers. The toolkit includes complete source code to create a library that will read and write 3dm files. OpenCASCADE providing services for 3D surface and solid modeling, CAD data exchange, and visulization. Most 阅读全文
摘要: Abstract. A root-finding algorithm is a numerical method, or algorithm, for finding a value x such that f(x)=0, for a given function f. Such an x is called a root of the function f. In OpenCASCADE math package, implemente Newton-Raphson method to find the root for a function. The algorithm can be used for finding the extrema value for curve or surface, .i.e Point Inversion, find the parameter for a point on the curve or surface. The paper focus on the usage of OpenCASCADE method and its applicat 阅读全文
摘要: Abstract. DWG is a file format created in the 70’s for the emerging CAD applications. Currently it is the native file format of AutoCAD, a proprietary CAD program developed by Autodesk. Libredwg is a free C library to read and write DWG files. This program is part of GNU project, released under the aegis of GNU. The paper focus on the usage of Libredwg, and use the Libredwg to read a DWG file and output the entities of the DWG to Tcl script for OpenCASCADE Draw Test Harness visualization.
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摘要: Abstract. The conic sections and circles play a fundamental role in CAD/CAM applications. Undoubtedly one of the greatest advantages of NURBS is their capability of precisely representing conic sections and circles, as well as free-form curves and surfaces. We assume a knowledge of conics and circles, the purpose of this paper is to study them in the framework of their representation as NURBS curves.
Key Words. OpenCASCADE, Conic Curves, Circle, Convert, BSpline Curve 阅读全文
摘要: Abstract. Rational Bezier Curve can represent conic curves such as circle, ellipse, hyperbola, .etc. But how to convert a conic curve to BSpline curve is still question, i.e. Represent a conic curve in BSpline form. The key point of Hyperbola conversion is to calculate the 2nd pole and its weight factor. The paper focus on the hyperbola convert to the BSpline curves.
Key Words. OpenCASCADE, Convert, Hyperbola, BSplineCurve, Conic Curve 阅读全文
摘要: Abstract. Rational Bezier Curve can represent conic curves such as circle, ellipse, hyperbola, .etc. But how to convert a conic curve to BSpline curve is still question, i.e. Represent a conic curve in BSpline form. Parabola curve is the most simple conic curve, that the parabola does not require rational functions. Let’s begin from the simplest one...
Key Words. OpenCASCADE, Convert, Parabola, BSplineCurve, Conic Curve 阅读全文
摘要: Abstract. When you are familiar with OpenCASCADE on Windows, you should try it on Linux operating system, because of Debian is also open source like OpenCASCADE. The paper is focus on how to building the OpenCASCADE on Debian.
Key Words. OpenCASCADE, Linux, Debian, Building 阅读全文
摘要: Debian是OpenCASCADE用于Linux操作系统测试的专用系统。这几天下载安装了Debian系统，体验了一下，感觉还不错：简洁，精致。
解决了这些问题后，Debian用起来感觉还好，还需要慢慢熟悉和适应。下一步准备在Debian上编译、调试C/C++程序。为编译OpenCASCADE的Linux版本打下基础。 阅读全文
摘要: Abstract. Use the Draw Test Harness to test the performance of OpenCASCADE by Tcl scripts. From the test result, you will check whether the OpenCASCADE meet your need.
Key Words. OpenCASCADE, Performance Test, Draw Test Harness, Tcl/Tk, 性能测试 阅读全文
摘要: Abstract. The color scale is a specialized label object that displays a color map and an accompanying numerical scale for color mapped or contour data plots. As the geometry modeling kernel of SALOME, OpenCASCADE provides the color scale function. The paper focus on the usage of color scale in OpenCASCADE.
Key Words. OpenCASCADE, Color Scale, 应力云图, 颜色映射表 阅读全文
摘要: Abstract. Although polynomials offer many advantages, there exist a number of important curve and surface types which cannot be represented precisely using polynomials, e.g., circles, ellipses, hyperbolas, cylinders, cones, spheres, etc. So we introduce the concepts of rational curves and homogeneous coordinates to solve the problem. To understand rational curves in a homogenous coordinate system is more straightforward. If you define irrational Bezier curves in 4D space and then project them ba 阅读全文
摘要: Abstract. Numerical integration is the approximate computation of an integral using numerical techniques. The numerical computation of an integral is sometimes called quadrature. The most straightforward numerical integration technique uses the Newton-Cotes formulas(also called quadrature formulas), which approximate a function tabulated sequence of regularly spaced intervals by various degree polynomials. If the functions are known analytically instead of being tabulated at equally spaced inter 阅读全文
摘要: Abstract. Doxygen is the de facto standard tool for generating documentation from annotated C++ sources, but it also supports other popular programming languages. You can also use doxygen for creating normal documentation, as OpenCASCADE did for its references and user’s guide documents.
Key Words. OpenCASCADE, Doxygen, Documentation System 阅读全文
摘要: Abstract. Add page number for Foran pipe spool drawing generated by ISOM. The ISOM of Foran is used for spool drawing generation, but there is no number on the drawing, so use AutoLISP to write a small plugin to add page number automatically.
Key Words. Foran, ISOM, Pipe Spool Drawing, AutoLISP, OpenCASCADE
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摘要: Abstract. The natural parametric equations of a curve are parametric equations that represent the curve in terms of a coordinate-independent parameter, generally arc length s, instead of an arbitray variable like t or u. According to the natural equations, the curve length is the integration of the curve parametric equation’s derivation. So the core algorithm for curve length calculation is the numerical integration method. OpenCASCADE use Gauss-Legendre to calculate the integration for single v 阅读全文
摘要: Abstract. OpenCascade uses advanced text rendering powered by FTGL library. The FreeType provides vector text rendering, as a result the text can be rotated and zoomed without quality loss. FreeType also support unicode charset. The paper focus on the Chinese Text rendering.
Key Words. OpenCascade, FreeType, Chinese Text, 中文汉字, Unicode 阅读全文
摘要: Abstract. Draw is a command interpreter based on Tcl/Tk and a graphical system used to test and demonstrate OpenCascade modeling libraries. It provides a flexible and easy to use means of testing and demonstrating the OCCT modeling libraries. By a given command of Tcl, you can find the implentation code for that command by OpenCascade, the code could be as a demo to use of OCC modeling libraries. So this is the most effectively way of use OpenCascade.
Key words. OpenCascade, Tcl/Tk, Tes 阅读全文
摘要: Abstract. Delaunay Triangulation is the core algorithm for mesh generation. By Delaunay Triangulator you can make a general method to visualize geometry surfaces, so does OpenCascade. The paper focus on the geometry surfaces visualization, include the surfaces with holes.
Key words. OpenCascade, Delaunay Triangulator, OpenSceneGraph, Mesh, NURBS 阅读全文
摘要: Abstract. B-splines are quite a bit more flexible than Bezier curves. This flexibility comes from the fact that you have much more control over the basis functions. For Bezier curves that each control point had an effect on each point on the curve; likewise the number of control points affected the degree of the curve. For the sake of flexiblity, you would like to be able to arbitrarily set the degree of the curve and to also determine the range of the affect each control point has. B-splines al 阅读全文
摘要: 从OpenCascade6.7.0开始图形显示的初始化部分有较大改动，将原来给出的一个关于Qt的最简单的例子程序升级到最新版本. 阅读全文
摘要: Try HOOPS 3D Part Viewer!
Great pictures... 阅读全文
摘要: Abstract. OpenCascade use the Jacobi method to find the eigenvalues and the eigenvectors of a real symmetric square matrix. Use class math_Jacobi to computes all eigenvalues and eigenvectors by using Jacobi method. The exception NotSquare is raised if the matrix is not square. No verification that the matrix is really symmetric is done.
Key words. Eigenvalues, Eigenvectors, OpenCascade, Matrix, Jacobi method, 阅读全文
摘要: Abstract. The ModelDataExchange import utility enables the user to import geometric models of equipment into 3D models within Design. The input models files format are STEP, IGES, STL .etc. The imported model is saved in polyhedron of the equipment.
Key Words. ModelDataExchange, Import, MEI, Mechanical Equipment Inteface
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摘要: Abstract. In mathematics a Voronoi diagram is a way of dividing space into a number of regions. A set of points, called seeds, sites, or generators is specified beforehand and for each seed there will be a correspoinding region consisting of all points closer to that seed than to any other. The regions are called Voronoi cells. It is dual to the Delaunay triangulation. It is named after Georgy Voronoy, and is also called a Voronoi tessellation, a Voronoi decomposition, a Voronoi partition, or a 阅读全文
摘要: Abstract. AVEVA Review is used to 3D model visualization for plant or ship design, construction and operation. Taking data from a range of 3D design systems, AVEVA Review delivers a virtual reality view of a plant or ship which users from all disciplines can freely navigate to view areas of interest, communicate ideas or undertake reviews. Use AVEVA .Net can extract model from DESIGN database, and use AnyCAD .Net can visualize the model. This paper mainly focus on the usage of AnyCAD .Net, and a 阅读全文
摘要: Abstract. C++ lets us redefine the meaning of the operators when applied to objects. It also lets us define conversion operations for class types. Class-type conversions are used like the built-in conversions to implicitly convert an object of one type to another type when needed. A conversion operator provides a way for you to define how an object can be converted automatically to a different type. The paper gives some conversion operators examples in OpenCascade.
Key words. OpenCascad 阅读全文
摘要: Use Model Data Exchange Addin to export structure models for PDMS.
配置方法见：http://www.cppblog.com/eryar/archive/2013/05/01/199875.html
更新记录：http://www.cppblog.com/eryar/archive/2013/09/11/203182.html 阅读全文
摘要: Abstract. Rendering a generic surface is a two steps process: first, computing the points that will form the mesh of the surface and then, send this mesh to 3D API. Use the Triangle to triangulate the parametric space and then lifting map to the model 3D space. This is the main method to visualize the generic shaded surface. This paper show the OpenCascade triangulation of the parametric space and the map result: mesh in 3D model space. Use the method can visualize a generic surface.
K 阅读全文
摘要: Abstract. Triangle is a 2D quality mesh generator and Delaunay triangulator. Triangle was created as part of the Quake project in the school of Computer Science at Carnegie Mellon University by Jonathan R. Shewchuk. Triangle is a small C program and its Delaunay refinement algorithm for quality mesh generation is a hybrid one. It includes divide-and-conquer and incremental insertion algorithms and sweepline Delaunay triangulation algorithm. This paper is focused on the usage of the Triangle and 阅读全文
摘要: Abstract. MeshVS means Mesh Visualization Service. It can be used to representation mesh in different style, such as colored stress patterns mesh, mesh with text and mesh like vector(with arrow). So MeshVS usually used for CAE programming. This paper focus on the MeshVS usage.
Key words. OpenCascade, Mesh, MeshVS, Colored stress Patterns 阅读全文
摘要: Abstract. BRep is short for Boundary Representation. Boundary Representation gives a complete description of an object by associating topological and geometric information for solid modeling. In this case, objects are described by their boundaries. There are two types of information in BRep: Topological information and Geometric information. This paper is concerned with the Cone BRep in OpenCascade, and also show how to use Tcl script to dump cone BRep info.
Key words. OpenCascade, BRep 阅读全文
摘要: Abstract. BRep is short for Boundary Representation. Boundary Representation gives a complete description of an object by associating topological and geometric information for solid modeling. In this case, objects are described by their boundaries. There are two types of information in BRep: Topological information and Geometric information. This paper is concerned with the Torus BRep in OpenCascade, and also show how to use Tcl script to dump torus BRep info.
Key words. OpenCascade, BR 阅读全文
摘要: Abstract. BRep is short for Boundary Representation. Boundary Representation gives a complete description of an object by associating topological and geometric information for solid modeling. In this case, objects are described by their boundaries. There are two types of information in BRep: Topological information and Geometric information. This paper is concerned with the Cylinder BRep in OpenCascade, and also show how to use Tcl script to dump cylinder BRep info.
Key words. OpenCasca 阅读全文
摘要: Abstract. BRep is short for Boundary Representation. Boundary Representation gives a complete description of an object by associating topological and geometric information for solid modeling. In this case, objects are described by their boundaries. There are two types of information in BRep: Topological information and Geometric information. This paper is concerned with the sphere BRep in OpenCascade, and also show how to use Tcl script to dump sphere BRep info.
Key words. OpenCascade, 阅读全文
摘要: Abstract. BRep is short for Boundary Representation. Boundary Representation gives a complete description of an object by associating topological and geometric information for solid modeling. In this case, objects are described by their boundaries. There are two types of information in BRep: Topological information and Geometric information. This paper is concerned with the Box BRep in OpenCascade, and also show how to use Tcl script to dump box BRep info.
Key words. OpenCascade, BRep, 阅读全文
摘要: Abstract. 本文通过给出曲面上曲线PCurve的定义来对OpenCascade中的Curve On Surface进行理解，并介绍了OpenCascade对应的类BRep_CurveOnSurface实现。通过Tcl脚本输出的球的拓朴信息，分析PCurve的实际应用。
Key words. OpenCascade, ACIS, PCurve, Curve on Surface, Parametric Surface 阅读全文
摘要: Abstract. This paper is concerned with parametric curves and surfaces definitions, such as singular point and regular point and their application in OpenCascade. The two most common methods of representing curves and surfaces in geometric modeling are implicit equations and parametric functions. Successful geometric modeling is done using both techniques. When you use parametric functions to represent curves and surfaces, you need to pay attention for the characteristic of it, such as singularit 阅读全文
摘要: 摘要Abstract：正确设置网格面上点的法向，对几何体在光照等情况下显示得更真实，这样就可以减少顶点数量，提高渲染速度。本文通过将OpenCascade中的形状离散成网格数据后在OpenSceneGraph中显示，及使用OSG的快速法向osgUtil::SmoothingVisitor优化与使用OpenCascade来计算正确的法向的结果的对比，说明面法向量的重要性。
关键字Key Words：OpenCascade, OpenSceneGraph, Normal Averaging, Triangulation Mesh 阅读全文
摘要: 摘要Abstract：表面上某一点的法向量（Normal Vector）指的是在该点处与表面垂直的方向。对于平面，其上各点的法向是一样的，统一为这个平面的法向。对于曲面，各点具有不同的法向量。几何对象的法向量定义了它在空间中的方向，法向量是在进行光照处理时的重要参数。所以在显示造型算法离散曲面后的网格时，设置正确的法向量对场景的光照、光线追踪效果有直接影响。本文结合OpenCascade中代码，对其法向量的计算方法进行分析，稍加修改即可用到实际的程序中。
关键字Key Words：OpenCascade, Normal Vector, Mesh Normal, OpenSceneGraph, 阅读全文
摘要: 摘要Abstract：在工厂辅助设计（Plant Design）或船舶辅助设计（Ship Design）等CAD设计软件中建完模型后都会出安装图或制作图，这也是这类辅助设计软件的最终的一个输出，还有再就是输出材料数据用来对物资进行管理。OpenCascade提供的Hidden Line Removal算法可以对模型进行隐藏线消除，此功能可用来生成制作图和安装图。本文通过实例演示了HLR算法的效果。
关键字Key Words：OpenCascade, HLR, Hidden Line Removal,Pipe Model, Plant Design CAD, Ship Design CAD,
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摘要: 摘要Abstract：本文通过OpenCascade的Tcl/Tk和ACIS的Scheme的对比来说明脚本语言在程序中的重要作用。及通过在Tcl中实现自定义的命令来理解Draw Test Harness的实现，在此基础上更有利于对OpenCascade的理解，其中Draw Test Harness一些命令的实现可以做为程序实现的参考。
关键字Key Words：OpenCascade, Tcl/Tk, ACIS, Scheme, Test 阅读全文
摘要: 摘要Abstract：OpenCascade6.7.0中引入了光线跟踪算法的实现。使用光线跟踪算法可实现高质量的渲染效果，且可以使用GPU提升渲染效率。
关键字Key Words：OpenCascade, Ray Tracing
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摘要: 摘要Abstract：Tcl/Tk脚本可以很容易实现用户自定义的命令，方便的创建图形化的用户界面GUI，所以Tcl和Tk的应用领域几乎覆盖了图形和工程应用的全部范围，包括计算机辅助设计、软件开发、测试、仪器控制、科学可视化及多媒体方面。本文主要详解如何在C程序中使用Tcl来创建自定义的命令，并理解OpenCascade的Draw Test Harness的实现。
关键字Key Words：OpenCascade, Tcl/Tk, Draw Test Harness, Software Customization
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摘要: 摘要Abstract：Tcl/Tck脚本可以很容易实现用户自定义的命令，方便的创建图形化的用户界面GUI，所以Tcl和Tk的应用领域几乎覆盖了图形和工程应用的全部范围，包括计算机辅助设计、软件开发、测试、仪器控制、科学可视化及多媒体方面。即可以使用Tcl/Tk实现AVEVA中的PML类似的功能，允许用户自己编写简单程序实现程序的二次开发。
关键字Key Words：AVEVA, PDMS, PML, Tcl/Tk, Script Modeling
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摘要: 摘要Abstract：本文结合OpenCascade和Initial Graphics Exchange Specification来对IGES格式进行详细说明，理解IGES格式的结构，进而方便对OpenCascade中IGES格式文件读写的实现进行理解。
关键字Key Words：IGES、Open Cascade、Data Exchange 阅读全文
摘要: 摘要Abstract：本文主是对Netgen的库nglib的用法进行介绍。主要参考资料是Netgen用户指南。最后给出一个具体程序实例。
关键字Key Words：Netgen, nglib, Mesh
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摘要: 摘要Abstract：本文主要介绍如何对下载的Netgen源码进行编译生成Netgen程序和程序开发所需要的库nglib。
关键字Key Words：Netgen, nglib, Mesh Generator, OpenCascade, Triangulation 阅读全文
摘要: 摘要Abstract：对DXF文本格式进行详细介绍，并介绍了如何使用开源库dxflib对DXF文件进行读写操作，并将DXF文件中图形导入到OpenCascade。
关键字Key Words：DXF、Open Cascade、Data Exchange, dxflib 阅读全文
摘要: 摘要Abstract：通过对OpenCascade中的BRep数据的读写，理解边界表示法的概念及实现。理解了拓朴形状的数据结构，就对ModelingData模块有了清晰认识，方便OpenCascade其他模块如ModelingAlgorithms和Visiualization模块的理解。
关键字Key Words：OpenCascade, BRep, Topology, BRep Format 阅读全文
摘要: 摘要Abstract：现在的显示器大多数是光栅显示器，即可以看做一个像素的矩阵。在光栅显示器上显示的任何图形，实际上都是一些具有一种或多种颜色的集合。数学上精确表示的图形在显示器中只能用逼近的方式显示出来。本文主要对OpenCascade的BRep文件中用来显示曲线和曲面的离散数据结构进行说明。
关键字：OpenCascade, BRep, Polygon, Triangulation, Subdivision Curves, 阅读全文
摘要: 摘要Abstract：本文通过程序实例，将OpenCascade中的拓朴数据（边、面）离散化后在OpenSceneGraph中进行显示。有了这些离散数据，就可以不用OpenCascade的显示模块了，可以使用其他显示引擎对形状进行显示。即若要线框模式显示形状时，就绘制离散形状拓朴边后得到的多段线；若要实体渲染模式显示形状时，就绘制离散形状拓朴面得到的三角网格。理解这些概念也有助于理解显示模块的实现，及拓朴数据中包含的几何数据的意义。
关键字 Key Words：OpenCascade, polygon curve, triangulation,discrete edge, discrete face, OpenSceneGraph, OSG 阅读全文
摘要: 摘要Abstract：几何曲面是参数表示的曲面 ，在边界表示中其数据存在于BRep_TFace中，BRep_TFace中不仅包括了几何曲线，还包含用于显示的离散几何信息，如三角剖分数据。本文主要对OpenCascade的BRep表示中几何曲面进行说明，将在后面分析Topology部分的读写程序时来说明包含几何数据的三种拓朴结构中分别包括哪些几何信息。
关键字Key Words：OpenCascade BRep, Geometry Surface, Topology 阅读全文
摘要: 关键字KeyWords：OpenCascade,Line Aspect, Line Type
在OpenCascade的显示模块中，可以设置线型、消隐方式和离散精度等属性。这些属性都是在AIS_Drawer中设置。
AIS_Drawer类就是用来管理显示属性的。
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摘要: 摘要Abstract：几何曲线是参数表示的曲线 ，在边界表示中其数据存在于BRep_TEdge中，BRep_TEdge中不仅包括了几何曲线，还包含其他类型的几何信息。本文主要对OpenCascade的BRep表示中几何曲线进行说明，将在后面分析Topology部分的读写程序时来说明这三种拓朴结构中分别包括哪些几何信息。
关键字Key Words：OpenCascade BRep, Geometry Curve, Topology, Refactoring 阅读全文
摘要: 摘要Abstract：本文以一个具体实例，创建一个三通部件来说明PipeInfo的使用方法。
关键字Key Words：PipeInfo, AVEVA Paragon, Tee component
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摘要: 摘要Abstract：本文结合OpenCascade的BRep格式描述文档和源程序，对BRep格式进行分析，详细说明BRep的数据组织形式。本文主要通过对BRep文件中的Locations部分的读写代码进行分析，来完全理解OpenCascade中的Location部分。
关键字Key Words：OpenCascade, BRep Format, Location, Location Set 阅读全文
摘要: 摘要Abstract：看到国外的PipeData这个管子部件查询软件用的人还很多，也想做个类似的小工具。用过AVEVA的Paragon来做管子部件，感慨其软件的操作简单和强大的参数化功能，使得制作一切部件成为可能。PipeInfo也是一个参数化的管子部件定义及查询软件，可以自定义任意部件，不仅可以是管件，也包括支架等，操作方式与Paragon类似，且是三维显示，比PipeData二维的方式更直观。
关键字Key Words：PipeInfo, PDMS Paragon, PipeData, 阅读全文
摘要: 摘要Abstract：本文简要介绍了数学表达式解析求值的几款开源软件，并结合程序代码说明了OpenCascade中表达式包的用法。也简要介绍了表达式解析求值在AVEVA Paragon模块中的应用。
关键字Key Words：Expression, Paragon, OpenCascade Expr package, muParser, MTParser 阅读全文
摘要: 摘要Abstract：本文简要介绍了适配器模式（adapter pattern），并结合程序实例对OpenCascade中的拓朴与几何的适配器的使用进行说明。
关键字Key Words：OpenCascade、BRep、Topology、Geometry、Adapter 阅读全文
摘要: 摘要Abstract：本文简要介绍了几何造型中的边界表示法（BRep），并结合程序说明OpenCascade中的边界表示的具体实现，即拓朴与几何的联系。拓朴结构中的位置（Location）和朝向（Orientation）进行了详细说明。
关键字Key Words：OpenCascade、BRep、Topology、Geometry、Location、Orientation 阅读全文
摘要: Abstract：本文简要介绍了几何造型中的边界表示法（BRep），并结合程序说明OpenCascade中的边界表示的具体实现，即拓朴与几何的联系。对具有几何信息的拓朴结构顶点（vertex）、边（edge）、面（face）进行了详细说明。本文通过ACIS与OpenCascade进行对比来对拓朴（Topology）的概念进行说明。并通过示例程序，说明如何在OpenCascade中取得与一个拓朴对象相连的其他拓朴对象，包括父对象和子对象。
关键字Key Words：OpenCascade、ACIS、BRep、Topology、Geometry 阅读全文
摘要: 摘要Abstract：本文简要介绍了几何造型中的边界表示法（BRep），并结合程序说明OpenCascade中的边界表示的具体实现，即拓朴与几何的联系。对具有几何信息的拓朴结构顶点（vertex）、边（edge）、面（face）进行了详细说明。本文仅对面（Face）进行说明。
关键字Key Words：OpenCascade、BRep、Topology、Geometry、Face 阅读全文
摘要: 摘要Abstract：介绍了ACIS与OpenCascade中的Seam edge和Degenerated edge。通过对比学习，更好地理解了Seam Edge和Degenerated Edge的概念。
关键字Key Words：ACIS、OpenCascade、Seam Edge、Degenerated Edge 阅读全文
摘要: 摘要Abstract：本文简要介绍了几何造型中的边界表示法（BRep），并结合程序说明OpenCascade中的边界表示的具体实现，即拓朴与几何的联系。对具有几何信息的拓朴结构顶点（vertex）、边（edge）、面（face）进行了详细说明。本文只对拓朴边数据进行说明，着重介绍了OpenCascade中两个种特别的边缝合边（seam edge）和退化边（degenerated edge）。
关键字Key Words：OpenCascade、BRep、Topology、Edge、Geometry
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摘要: Abstract：以一个经典的Hello World程序为例开始对开源几何造型内核OpenCascade的学习。
关键字Key Words：OpenCascade、Qt、Hello World 阅读全文
摘要: Abstract：本文简要介绍了几何造型中的边界表示法（BRep），并结合程序说明OpenCascade中的边界表示的具体实现，即拓朴与几何的联系。对具有几何信息的拓朴结构顶点（vertex）、边（edge）、面（face）进行了详细说明。本文只对顶点数据进行说明。
关键字Key Words：OpenCascade、BRep、Topology、Geometry 阅读全文
摘要: Abstract：详细介绍了如何在Qt中使用OpenCascade。
关键字Key Words：Qt、OpenCascade 阅读全文
摘要: 本文对OpenCascade中的几何类型进行简要介绍。文章内容来源为OpenCascade的介绍文档overview。
关键字Key Words：OpenCascade、Geometry 阅读全文
摘要: 本文对OpenCascade中的几何曲面数据进行简要说明，并结合OpenSceneGraph将这些曲面显示。
关键字Key Words：OpenCascade、OpenSceneGraph、Geometry Surface、NURBS 阅读全文
摘要: 本文对网格数据结构作简要介绍，并结合使用OpenCascade中的数据结构，将网格数据在OpenSceneGraph中可视化。
关键字KeyWords：OpenCascade、OpenSceneGraph、Triangulation、Mesh Data Structure 阅读全文
摘要: 本文简要说明OpenCascade中几何曲线的数据，并将这些几何曲线在OpenSceneGraph中绘制出来。
关键字KeyWords：OpenCascade、Geometry Curve、OpenSceneGraph、B-Spline、NURBS 阅读全文
摘要: 本文结合OpenCascade的BRep格式描述文档和源程序，对BRep格式进行分析，详细说明BRep的数据组织形式。结合源程序，可以对OpenCascade中Modeling Data模块中的模型数据结构进行理解。
关键字Key Words：OpenCascade, BRep Format, ModelingData
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摘要: 本文结合OpenCascade的BRep格式描述文档和源程序，对BRep格式进行分析，详细说明BRep的数据组织形式。结合源程序，可以对OpenCascade中Modeling Data模块中的模型数据结构进行理解。
关键字Key Words：OpenCascade, BRep Format, ModelingData
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摘要: 本文对矩阵作简要介绍，并结合代码说明OpenCascade矩阵计算类的使用方法。
关键字Key Words：OpenCascade、Matrix、C++ 阅读全文
摘要: 测试STL的三维的模型文件hand.stl。 阅读全文
摘要: sgCore是由Geometros公司创建的实体造型库，是其公司的一个产品SolidGraph（参数化CAD系统）的几何内核。sgCore只用C++开发，导出了约30多个类及实现了二维和三维造型中的大部分算法。如：布尔运算、放样和其他曲面。 阅读全文
摘要: 摘要：本文简要介绍了Delaunay三角剖分的基础理论，并使用OpenCascade的三角剖分算法将边界BRep表示的几何体进行三角离散化后在OpenSceneGraph中显示。
关键字：Delaunay Triangulation、OpenCascade、OpenSceneGraph 阅读全文
摘要: 摘要Abstract：分析幂基曲线即多项式曲线在OpenCascade中的计算方法，以及利用OpenSceneGraph来显示OpenCascade的计算结果，加深对多项式曲线的理解。
关键字Key Words：OpenCascade、PLib、OpenSceneGraph、Polynomial Library 阅读全文
摘要: 企业应用三维CAD进行产品创新设计已经是一各必然趋势，三维设计符合人的思维习惯。在二维CAD普及的今天，三维CAD也就成为我国加快实现工业现代化的必然选择，其对制造业增强产品创新开发能力起到了巨大的推动作用，是制造业信息现代化建设不可或缺的工具。然而目前我国制造业中普及三维CAD还存在许多现实的问题，三维CAD软件的产业化开发水平远不如二维CAD软件。因此，发展具有自主知识产权的三维CAD软件，打破国外产品的垄断局面，成为一项非常迫切的任务。 阅读全文
摘要: 摘要Abstract：介绍了三维数据交换格式STL的组成，以及Open Cascade中对STL的读写。
关键字Key Words：STL, Open Cascade, Data Exchange 阅读全文
摘要: 将AVEVA中设备模型转换成STEP、IGES、STL、3DS格式，以便于将模型导入到其它CAD软件中。
The Model Data Exchange Addin allows the user to extract 3D geometric models from the DESIGN databases and output them in STEP, IGES, STL format. Those file format can be used to import 3D geometry into the systems that can read the format, such as Autodesk® 3D Max, Pro/E, etc. 阅读全文
摘要: 摘要Abstract：直接根据B样条的Cox-deBoor递推定义写出计算B样条基函数的程序，并将计算结果在OpenSceneGraph中显示。
关键字Key Words：B Spline Basis Functions、OpenSceneGraph
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摘要: 君子性非异也，善假于物也。
在学习计算机辅助几何造型（CAGD）等内容时，总是想把NURBS曲线、曲面显示出来，这样才能领会其中的奥妙。而现在大部分的教材都只是给出定理及其相关性质的证明，编程实现曲线及曲面显示的书籍很少。
OpenSceneGraph是使用OpenGL技术开发的一套C++编程接口，借助这个工具可以让程序员能够更加快速、便捷的创建高性能、跨平台的交互图形程序。使用OpenSceneGraph可以让程序员只关注其算法，显示部分都由OSG来完成。osgViewer完成了视图操作的大部分功能，如旋转、缩放、移动，另外还有统计功能。 阅读全文
摘要: 摘要Abstract：简要介绍Open Cascade中的B样条曲线库BSplCLib的使用方法，并且结合源程序来对Open Cascade中的B样条曲线的组成部分如节点矢量、重复度等概念进行介绍，以及通过对计算B样条基函数的算法进行分析，加深对B样条曲线概念的理解。 阅读全文
摘要: 在学习曲线和曲面时，总是希望将计算结果显示出来，这样便于对数学公式形成更直观的认识，可以借助工具OpenGL来将实现。对于曲线或以使用GL_LINE_STRIP来将曲线上的离散点连接起来形成曲线；对于曲面可以使用三角形或多边形来将曲面上的离散点连接起来形成曲面。 阅读全文
摘要: Open Cascade造型算法——倒圆与倒角
Modeling Algorithms Fillets and Chamfers 阅读全文
摘要: Open Cascade中的布尔操作
Modeling Algorithms Boolean Operations
布尔操作（Boolean Operations）是通过两个形状（S1，S2）的组合来生成新的形状。布尔操作有如下几种类型：
u 并集操作Fusion：Gets all the points in S1 or S2;
u 交集操作Common：Gets all the points in S1 and S2;
u 差集操作Cut S1 by S2：Gets all the points in S1 and not in S2;
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摘要: 在Open Cascade中创建基本几何实体 阅读全文
摘要: 在几何建模的过程中，程序创建和删除了大量的对象在动态内存中，也就是堆中。在这种情况下，标准C++的内存管理方式不是很高效，所以Open Cascade在包Standard中专门写了个内存管理程序（Memory Manager）来对内存的分配与删除进行管理。 阅读全文
摘要: 对应的new和delete要采用相同的形式
尽量用new和delete而不用malloc和free
From: Effective C++ 阅读全文
摘要: 本文简要介绍了借助于开源的几何造型内核OpenCASCADE把从AVEVA Plant(PDMS)中导出的数据重新以三维展示，类似AVEVA Review的功能；以及利用OCC的数据交换功能模块，将导出的数据转换成常见三维数据标准存储格式，便于其它CAD之间的数据交换，类似Mechanical Equipment Interface的功能。 阅读全文
摘要: 当在OpenCASCADE中使用BRepPrimAPI_MakeTorus创建一个有角度的Torus时，出现了问题，结果仍然是一个完整的，并且还带有些不需要的形状出现，而且会使程序变得缓慢。 阅读全文
摘要: Euler Angle
quaternion 阅读全文
摘要: 因为OpenCascade有自己的内存管理机制，所以要将MFC的
#ifdef _DEBUG
#define new DEBUG_NEW
#endif
宏定义去掉。
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