SOLID MODELING翻译.doc

SOLID MODELING实体造型6.1 Application of Solid Models实体模型的应用In mechanical engineering, a solid model is used for the following applications:在机械工程中，一个实体模型被用于以下应用：1、 Graphics: generating drawings, surface and solid models图形：生成图纸，表面和实体模型2、 Design: Mass property calculation, interference analysis, finite element modeling, kinematics and mechanism analysis, animation, etc.设计：质量计算、干涉分析、有限元建模、运动学及机理分析、动画等。3 、Manufacturing: Tool path generation and verification, process planning, dimension inspection, tolerance and surface finish.制造业：刀具轨迹的生成和验证，工艺设计，尺寸检验，公差及表面处理。4 、Component Assembly: Application to robotics and flexible manufacturing: Assembly planning, vision algorithm, kinematics and dynamics driven by solid models.组件组装：应用于机器人和柔性制造：装配规划，视觉算法，运动学和动力学模型的驱动。6.2 Solid Model Representation实体模型表示There are three different forms in which a solid model can be represented in CAD:有三种不同的形式，其中一个实体模型可以表示在计算机辅助设计： Wireframe Model线架模型 Surface Model曲面模型 Solid Model实体模型Wireframe Models: Joining points and curves creates wireframe models. These models can be ambiguous and unable to provide mass property calculations, hidden surface removal, or generation of shaded images. Wireframe models are mainly used for a quick verification of design ideas.线框模型：连接点和曲线创建线框模型。这些模型可以是模糊的，无法提供质量的计算，隐藏的表面去除，或产生的阴影图像。线框模型主要用于快速验证设计思路。Surface Models: Surface models are created using points, lines, and planes. A surface model is unable to identify points that do not lie on the surface, and therefore, the moment of inertia, volume, or sections of the model cannot be obtained. A surface model can be shaded for better visibility. Surface models are used for modeling surfaces of engineering components.表面模型：使用点、线、面创建表面模型。表面模型是无法识别的点，不在于表面上，因此，该时刻的惯性，体积，或部分的模型不能得到。一个表面模型可以被遮蔽，以更好的能见度。表面模型被用于工程部件的建模表面。Solid models: Solid models are the most preferred form of CAD models. and represent unambiguous image of a component. A solid model can be used to analyze the moment of inertia, mass, volume, sections of the model, etc.固体模型：固体模型是最优选的计算机辅助设计模型。一个组件的明确的图像。一个实体模型可以用来分析惯性矩，质量，体积，截面的模型等。Solid models are mathematical models of objects in the real world that satisfy specific properties, listed below.实体模型是在现实世界中的对象的数学模型，满足特定的属性，下面列出。1、Bounded: The boundary must limit and contain the interior of the solid.有界：边界必须限制并包含固体的内部2、Homogeneously Three-Dimensional: No dangling edges or faces be present so that the boundary is always in contact with the interior of the solid.均匀地三维：没有悬空的边缘或面是目前的边界是总是在接触的固体的内部。3、Finite: The solid must be finite in size.有限：固体必须是有限的大小。6.3 Solid Model Creation Scheme实体模型创建方案A solid model can be generated by the following schemes.一个实体模型可以由以下方案生成。1、 Constructive Solid Geometry (CSG)构造实体几何（CSG）2、 Boundary Representation (B-Rep)边界表示法（B-rep）3、 SweepingA brief description of these schemes follows.这些计划的简要说明如下6.3.1 Constructive Solid Geometry Scheme构造性立体几何方案This scheme is based on the principle that two primitives can be combined to produce a new solid model. This method is also known as “building Block”method. The scheme uses the Union, Intersection, and Subtraction techniques to create three-dimensional models, which are based on the Boolean operation. The steps involved in generating a solid model are:此方案是基于这样的原则，可以结合起来，以产生一个新的固体模型的基本原理。这种方法也被称为“积木”方法。该方案使用的联盟，交叉，和减法技术，创建三维模型，这是基于布尔运算。产生一个实体模型所涉及的步骤是：1、Select the primitives from a library从库中选择基元2、Go through the scaling, dimension modification, and any other transformations.通过缩放，尺寸修改，和任何其他转换。3、Combine the primitives to create the desired solid model.结合原语创建所需的实体模型Since CSG method uses solid primitives, internal details of the object are automatically contained in the model. The model can be sectioned to reveal internal details and can be used for calculating mass, volume, moment of inertia, etc.由于CSG方法使用固体元素，对象的内部细节被自动包含在模型。该模型可以切片揭示内部细节和可用于计算质量、体积、惯性矩、等。New solid models can be created from the primitives or other solid models by the following operations:新的实体模型可以从原语或其他实体模型中创建，通过以下操作：Union (U): Two solids are joined and the common volume of one of the primitives is neglected in the resulting solid.联合（美国）：2个固体的加入和一个基本的共同体积是被忽视的固体。Subtraction or Difference (-): One solid is subtracted from the other and the resultant solid retains only the uncut portion of the solid.减法或差（-）：一个是从其他所得固体只保留固体未删节的部分减去。Intersection (n): When two solids are combined, the resultant solid represents the common volume of the two solids.交叉点（氮）：当2个固体相结合时，所得到的固体代表固体的共同体积。The most common primitive solids found in a CAD program are:在计算机辅助设计程序中发现的最常见的原始固体：Block, Cylinder, Cone, Sphere, Wedge, and Torus.块，圆柱体，锥，球，楔，和环面6.3.2 Boundary Representation (B-Rep) Scheme边界表示法（B-rep）方案This scheme is based on the concept that a physical object is bounded by a set of faces. A solid model is created by combining faces and contains vertices, edges, loops, and bodies. Only the boundary surfaces of the model are stored and the volumetric properties are calculated by the Gauss Divergence theorem, which relates volume integral to surface integrals. This scheme can model a variety of solids depending on the primitive surfaces (planar, curved, or sculptured). There are two types of solid models in this scheme:此方案是基于一个物理对象是有界的一组人脸的概念。一个实体模型是建立在结合面和包含顶点，边，循环，和机构。只有边界曲面模型的存储和由高斯散度定理计算的体积性质，涉及体积表面积分积分。该方案可以模拟各种不同的原始表面（平面、曲面、固体或雕塑）。该方案中有2种类型的实体模型：1、 Polyhedral solids多面体固体2、 Curved solids曲面1. Polyhedral Solids: Polyhedral models consist of straight edges, e.g., a non-cylindrical surface: box, wedge, combination of two or more non-cylindrical bodies, etc. Polyhedral solids can have blind or through holes, and two or three-dimensional faces, with no dangling edges. A valid polyhedral abides by the Eulers equation:多面体：多面体模型包括直边，例如，非圆柱面：箱，楔，组合的2个或多个非圆柱形物体等。多面体的固体可以有盲或通过孔，和2或三维面，没有悬空边。一个有效的多面体遵循欧拉方程：F - E + V - L = 2 (B-G)Where,F = Face E = Edge V = Vertices L = Inner Loop B = Bodies G = Through holesA simple polyhedral has no holes; each face is bounded by a single set of connected edges (bounded by one loop of edges).一个简单的多面体有没有孔，每个面是有界的一组连接的边（边的一个循环）。Primitives: In B-rep, a model is made up of the following primitives:图元：在边界，模型由以下元素：Vertex: A point in space顶点：空间上的点。 Edge: A finite, no-intersecting space curve bounded by two vertices that are not necessarily distinct.边：一个有限的，不相交的空间曲线，由2个顶点，不一定是不同的。Face: A finite connected, non-self-intersecting, region of a closed oriented surface, bounded by one or more loops.面：一个有限连通，非自相交，区域的一个封闭的表面，有界的一个或多个循环。 Loop: An ordered alternating sequence of vertices and edges. A loop defines a non-self-intersecting closed space curve, which may be a boundary of a face.循环：顶点和边的有序交替序列。一个循环定义了一个非自相交的封闭空间曲线，这可能是一个面。Body: Entity that has faces, edges and vertices. A minimum body is a point.一个具有面、边和顶点的实体。最小身体是一个点。B-rep scheme is closely related to the traditional drafting method.B方案是传统的绘图方式密切相关。6.3.3 Sweeping Scheme扫描方案Sweeping can create a solid model. The method is useful for creating 2 - dimension models. The generated models are axisymmetric and have uniform thickness (i.e., extruded models). There are two types of sweeps: linear and rotational. In linear sweep, a closed 2-D sketch is extruded through the desired length, creating a homogeneous and axisymmetric model, as shown in the figure.扫可以创建一个实体模型。该方法可用于创建2维模型。所产生的模型是轴对称的，具有均匀的厚度（即，挤压模型）。有2种类型的扫描：线性和旋转。在线性扫描，一个封闭的二维草图是挤压通过所需的长度，创建一个均匀的和轴对称模型，如图所示。In addition to the two sweeps described above, a model can also be created by a non-linear sweep. In this type of sweep, a closed sketch is sweeped along a non-linear path.除了上面描述的2个扫描外，还可以通过一个非线性扫描来创建一个模型。在这种类型的扫描，一个封闭的草图是席卷沿非线性路径。6.4 Commercial Modelers商业模型Most commercial software use the sweeping scheme. ProE and Solidworks are good examples of software that utilize sweep technique to generate a 3-D model. In both of these programs, a 2-D sketch is created and extruded to generate a 3-D base-model. The base model is then used to add or modify features. Most engineering components can be created by this technique.绝大多数商业软件使用了扫描方案。ProE，Solidworks软件是很好的例子，利用扫描技术生成三维模型。在这两种方案中，一个二维草图