随笔分类 - 3. ModelingData
Geometry Data structure.
Topology Data structure.
Topology Data structure.
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。
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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。
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摘要：
OpenCASCADE曲线向曲面投影。
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OpenCASCADE曲线向曲面投影。
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摘要：
OpenCASCADE 投影生成PCurve
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OpenCASCADE 投影生成PCurve
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摘要：
BRep_Builder的Add和Remove注意事项。
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BRep_Builder的Add和Remove注意事项。
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摘要：OpenCASCADE中计算直线与平面的交点
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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。
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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。
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摘要：OCCT的TopoDS允许定义只包含显示数据的BRep体，如只包含边的显示数据：多段线；面的显示数据：网格，而不包含几何曲线和曲面。只包含显示数据的BRep体有时候很有用，如只需要显示一下而不对其做任何修改。但是OCC7.3.0版本之前是不支持这些显示数据的。
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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
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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
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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
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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,Gauss
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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
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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
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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
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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
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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. OpenC
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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
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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
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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,
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