基于CATIA的汽车三视图逆向三维建模

文章基于CATIA自由曲面反求技术,对车身曲面设计进行了研究。通过对宝马三视图的数据采集和处理、曲面的构建以及曲面分析,进行车身曲面的数字化建模,反求出汽车曲面的三维数字模型。解决了通过三视图实现快速逆向工程实体三维数字建模问题。     

用Rhino、3dsmax优化工程制图

在传统的工程制图中，三视图、透视图及效果图被分别独立地制作，且三视图易读性不强。首次提出工程制图的“一步到位”思路与三视图的“2．5维”概念，不但大大提高了作图效率，又增强了工程图的易识读性。     

巧用Auto CAD绘制三视图

提出了用Auto CAD快速，准确绘制三视图，保证三视图之间投影规律的几种方法，并有例子详细介绍了这几种方法的操作过程。     

利用类似性识读切割体三视图

读懂三视图是学习机械制图的主要目的之一,而如何识读切割体的三视图更是读图中的重点与难点,但如果能够用所学到的类似性的知识去识读切割体的三视图的话,会让我们受益匪浅。     

利用Salt将AutoCAD的三视图转换三维立体图的方法

目前根据三视图来完成三维图的绘制比较复杂。利用基于AutoCAD的软件Adaucogit Salt,可以快速地实现三视图转换为三维立体图。Salt解决了工程师制图的繁琐过程,提高了工作效率,使设计者集中心力于创新。     

基于三视图的分布式数控系统模型及其实现

将三视图的思想用于分布式数字控制（ＤＮＣ）系统的分析和设计过程中，以面向对象方法作为主视图，建立了一种基于三视图的ＤＮＣ系统形式模型，并对基于这种模型的ＤＮＣ系统体系结构进行了描述；以实体—关系图和事件—响应模型作为辅助视图构建了类表示模型，提出了一种资源可重用的ＤＮＣ系统解决方案。     

借助工程数学理论计算机械零件三视图研究

概要地论述了运用工程数学理论计算机械零件三视图(工程图学)问题,这对参数化设计、制造(如数控加工)的意义是十分重要的.机械零件的表达方法源于数学,随着机械制造业的不断发展和完善,它还必将回归数学;介绍了应用工程数学手段解决机械零件三视图问题的思想,这类问题将越来越多地用数学方法来解决;并着重介绍了应用工程数学理论计算机械零件三视图的方法问题.     

AutoCAD绘制组合体三视图的方法与技巧

在AutoCAD中绘制组合体三视图既方便又快捷，首先，应明确绘制组合体三视图的方法与步骤；其次，需经过反复练习，从不断的操作中熟练掌握直线和圆等绘图命令，偏移和镜像等编辑命令，体会对象捕捉和极轴追踪等精确绘图功能的操作技巧。     

多媒体技术在工程制图教学中的应用

针对《工程制图》课程内容的特点，通过对组合体三视图的分析，说明将传统教学法和多媒体技术融于一体的教学模式可以取长补短，更有效地提高学生的空问想象力。     

机械制图学习模型库的制作

主要介绍了用Pro／E创建一个三维实体并用VB建立模型库的操作,以实体间的相交、相切、共面的挖切和叠加进行组合体的创建,分类建立实体三维模型,并给出相应的三视图。通过模型库的制作和学习,既可以熟练机械制图的计算机相关操作,又可以通过对已有模型的学习积累形象素材,从而培养学生更好地理解三视图的空间构思能力。     

快速实现AutoCAD三视图宽相等的开发方法

在AutoCAD2004环境下,利用ARX开发工具,根据我国绘制机件三视图的制图标准,开发了一个快速实现三视图中俯、左视图宽相等的ARX应用程序。论述了程序的实现方法,以及程序实现过程中的一些关键技术,如图中实体最大、最小X、Y坐标值的获取方法、辅助线图层的生成方法等。利用该程序,用户只要拾取俯视图或左视图中的一点,程序就可以快速找到它在左视图或俯视图中对应的宽度位置,并自动画出辅助线。该程序已用于某机械CAD中,大大提高了设计和绘图的效率。     

面向产品全生命周期的xBOM研究

在产品全生命周期中，存在各种面对企业不同部门和用途的BOM视图，为有效地保证了BOM视图之间的数据完整性，正确性和一致性，提出了BOM视图之间的转换方法。通过定义虚设部件，中间部件和外协部件及其相关映射函数，实现了设计BOM、工艺BOM和制造BOM之间的转换，并在制造BOM的基础上，实现了采购BOM等其他BOM的快速快建。     

A neural network approach to the classification of 3D prismatic parts

This paper presents a neural network approach to the classification of 3D prismatic parts based on their global shape information modelling. In this approach, a 3D part is modelled by the contours of its three projected views, which are approximately represented by three rectilinear polygons. The global shape information of each polygon is modelled by its simplified skeleton, which originally is of a tree structure and can be represented by several vectors by a conversion method. These vectors are the input to a polygon classifier which is constructed on the basis of the back-propagation neural network model. The classification results of polygons can be used to group the 3D prismatic parts into families in a hierarchical manner, by setting different levels of similarity criteria. The proposed method for classifying 3D workpieces can be used to enhance the productivity of design and manufacturing processes. By retrieving and reviewing similar parts from the part families, the designers or process planners could be greatly assisted in performing a new task. That is, they can avoid the reinvention of an existing design and can create a new design by modifying existing ones.     

数控机床使用中的安全问题

以FANUC系统为例，针对编程时工件坐标系和基准点的设定、书写小数点、调整和取消刀具长度偏置、刀具号与刀具补偿号的核心核对和设定、轮廓铣削时存在的隐患，进行了详细的分析，并提出了相应的防范措施。     

Structural view independence: A criterion for judging the objectivity of economic parameters measured by opinion survey

Economic measurements have a great influence over all our lives, but as with other soft measurements, significant effort is needed to ensure their objectivity. This is particularly true of the process of consolidating into a single representative figure different people’s valuations of a non-market good (“views”), as measured by opinion survey. Sometimes the views are transformed and averaged before being returned to the original domain as the back-transformed mean. Examples are the geometric mean resulting from a logarithmic transformation and the root-mean-squared (r.m.s.) value from a square transformation. Such transformations are tested for objectivity using the new criterion of structural view independence. It is shown that an analyst using any general, nonlinear, increasing and differentiable transformation other than the linear transformation can know at the outset that he is giving greater weight to views of his choosing, meaning that he has no claim to objectivity. Of all such transformations, only the linear transformation possesses the desirable property of structural view independence. The resultant sample mean is objective and the only consolidated figure recommended for human views.     

Extended fast-ion D-alpha diagnostic on DIII-D

A fast-ion deuterium-alpha (FIDA) diagnostic, first commissioned on DIII-D in 2005, relies on Doppler-shifted light from charge-exchange between beam neutrals and energetic ions. The second generation (2G) system was installed on DIII-D in 2009. Its most obvious improvement is the spatial coverage with 11 active in-beam and three passive off-beam views; the latter allows for simultaneous monitoring of the background signal. Providing extended coverage in fast-ion velocity space, the new views possess a more tangential component with respect to the toroidal field compared to their first generation counterparts. Each viewing chord consists of a bundle of three 1.5 mm core fibers to maximize light gathering. For greater throughput, fast f/1.8 optical components are used throughout. The signal is transmitted via fiber optics to a patch panel, so the user is able to choose the detector. FIDA was originally installed with a spectrometer and charge-coupled device (CCD) camera to monitor the full D(α) spectrum for two spatial views. 2G adds another spectrometer and CCD that monitor the blue-shifted wing for six spatial views at 1 kHz. In addition, a photomultiplier tube and fast digitizer provide wavelength-integrated signals at 1 MHz for eight spatial views.     

Axial tomographic confocal fluorescence microscopy

By physical rotation of the sample, axial tomography enables the acquisition of otherwise inaccessible spatial information from an object. In combination with confocal microscopy, the method can fundamentally improve the effective three‐dimensional (3D) resolution. In this report we present a novel method for high resolution reconstruction of confocal axial tomographic data. The method automatically determines the relative angles of rotation, aligns the data from different rotational views and reconstructs a single high resolution 3D dataset. The reconstruction makes use of a known point spread function and is based on an unconstrained maximum likelihood deconvolution performed simultaneously from multiple (in our case three) angular views. It was applied to simulated as well as to experimental confocal datasets. The gain in resolution was quantified and the effect of choice of overrelaxation factors on the speed of convergence was investigated. A clearly improved 3D resolution was obtained by axial tomography together with reconstruction as compared with reconstruction of confocal data from only a single angular view.     

一种支持多态特征转换的特征建模

在不同的工程应用中对特征有不同的定义方法。本文讨论了一种支持并行工程的特征建模方法，将一特征模型表示为三层：特征，正则形状，求解几何。在特征层定义了包括形状类型和有效约束的型特征，在正则形状层每一特征用参数化的实体表示，在求解几何层用一中心单元模型与各不同的工程应用相联系。不同的工程应用有各自不同的特征视角。本文的特征模型通过保持各视角的约束来保证其有效性。各视角的约束同存于造型系统中，用特征转换将变化在各视角间进行传播，从而保证各视角的一致性     

基于环搜索的盲台阶娄特征识别

提出了一种基于环搜索的盲台阶类特征识别方法。首先建立机械工程图二维正交投影视图的环描述，通过对盲台阶类特征的环构成的分析，定义能够反映盲台阶类特征的种子环，确定种子环的识别规则，从环集合中搜索符合特定规则的种子环，为盲台阶类结构特征的识别做好准备，然后，通过多视图的环匹配，实现盲台阶特征的识别。这种方法在实际 应用中取得良好效果，并可推广应用到具有类似特点的特征识别。