Technology & Engineering
Solid Modeling
Solid modeling is a technique used in computer-aided design (CAD) to create three-dimensional models of objects with complex geometries. It represents the physical volume of an object and is used for simulating and analyzing the behavior of the object in various conditions. Solid modeling is widely used in engineering, architecture, and manufacturing for designing and prototyping products.
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8 Key excerpts on "Solid Modeling"
- Dennis Lieu, Sheryl Sorby(Authors)
- 2016(Publication Date)
- Cengage Learning EMEA(Publisher)
5-1 T he widespread availability of computers has made three-dimensional modeling the preferred tool for engineering design in nearly all disciplines. Solid Modeling allows engineers to easily create mathematical models parts and assemblies, visualize and manipulate these mod-els in real time, inspect how they mate with other parts, and calculate their physical properties. The geometry of a part, as well as allowable errors, is determined to a large degree on the fabrication method used to make it. Thus, a basic under-standing of fabrication processes is important for creating three-dimensional designs. There are many available manufacturing processes, and all have advantages and disadvantages. Three- dimensional modeling also is used as the foun-dation for many sophisticated computational analysis techniques such as mass properties, interference checking, and finite element analysis. The ease with which this can be done has moved what was formerly a complicated analytical pro-cess performed by specialists into the realm of standard practice by many design engineers as part of the design process. CHAPTER 5 Solid Modeling 5-2 CHAPTER 6 Assembly Modeling 6-1 CHAPTER 7 Design Analysis 7-1 M O D E R N D E S I G N P R A C T I C E A N D T O O L S SECTION TWO Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.
eBook - PDF- George Zobrist, C Y Ho(Authors)
- 2000(Publication Date)
- CRC Press(Publisher)
10 Representation and Conversion Issues in Solid Modeling Leila De Floriani Dipartimento di Informatica e Scienze delNnformazione Universita di Genova Via Dodecaneso, 35 16146 Genova, Italy Enrico Puppo Istituto per la Matematica Applicata Consiglio Nazionale delle Ricerche Via De Marini, 6 (Torre di Francia), 16149 Genova, Italy 1. INTRODUCTION The problem in giving a description of geometric objects within computer sys-tems has become more important in the last few years. The significant develop-ment of computer application fields dealing with solid objects, like CAD/CAM and robotics, motivates a research for effective and efficient solutions. Solid Modeling is an important discipline whose goal is to be able to express the entire nature of three-dimensional objects [50], and to make computer systems capable of answering geometric questions algorithmically [39]. Key points in designing a solid model are the capability of satisfying some general requirements, like completeness, integrity, regularity and so on, while giving a representation that is expressive and efficient enough to be used in practical applications. Several object representation schemes have been developed in the past for different applications; interesting classifications and discussions of such schemes are given in [39, 43, 50]. Some object models can be considered special-purpose , in the sense that they are devoted to represent special classes of objects. Among this class of models, we can mention sweep representations, generalized cylinders and cones, blob models, primitive instancing, prism-trees, and some 2 V 2 -dimensional representations (ternary and quaternary decompositions, quad-tree decompositions, cone trees, 2D triangulations). General-purpose models are characterized by a better descriptive power on a wide class of solid objects, and are often identified with the models that have been developed for direct support 374
- Laszlo Horvath, Imre Rudas(Authors)
- 2004(Publication Date)
- Academic Press(Publisher)
C H A P T E R Construction and Relating Solid Part Models in CAD/CAM Systems Part modeling is the historical area of computer aided design, drafting, and manufacturing. Traditionally, part models were con-structed individually and each part model was stored in a separate file. Now, five different aspects integrate part modeling in a comprehensive product modeling environment. They are: Associative modeling of engineering objects. Concurrent modeling in group work of engineers. Integration of wireframe , surface , and Solid Modeling. Modeling part variants and families , starting from the same geometry. Including knowledge in part models. During the 1970s and 1980s, computer aided engineering was concentrated on the modeling of parts and their manufacture. Complex surfaces and solids were represented by different meth-ods: their models were often constructed in different modeling systems. While curves and surfaces were represented by early 285 versions of Beziers and B-splines, Solid Modeling was based on an unevaluated form of constructive solid geometry with half space representations of solid primitives. Now, as explained above, uni-fied model representation ensures integrated construction of parts and other objects of mechanical products. Parts are modeled in an assembly context , surfaces are modeled in a part context , and kinematics are modeled in an assembly relationship context. In Figure 8-1, Parts 1 – 3 are modeled. Part modeling is inte-grated by surface and assembly modeling. Contours C 0 1 on Part 1 and C 1 on Part 2 are the same; they are created in the assembly space. Surface S 1 is created in a surface modeler and then inte-grated in Part 2 as a form feature by substituting a flat surface with it. The surface S 1 has specified continuity for its boundary curves. Position continuity (D0) is specified at three curves, tangent (D1) continuity at the fourth one. Tangent continuity probably needs modification of the surface.
eBook - PDF- Zhuming Bi, Xiaoqin Wang(Authors)
- 2020(Publication Date)
- Wiley-ASME Press Series(Publisher)
2.7 Summary A solid object consists of (i) geometric elements at different levels, from vertices to edges, faces, volumes, and features, and (ii) the topological relations of geometric elements. Geometric modelling is used to create computer representations of solid objects, while Computer Aided Geometric Modelling 81 geometric modelling lays the foundation for using computer aided techniques. The com- monly used modelling methodologies include wireframe modelling, surface modelling, space decomposition, constructive solid geometric modelling, and feature-based modelling. The information of geometric representation of an object from different modelling meth- ods may be different. A wireframe model consists entirely of points, lines, and curves; it does not have the information for face or volume, and no topological data are needed in modelling. A surface model stores the topological information in corresponding objects, but a surface model can still be ambiguous in some cases. Both a surface model and a solid model can be utilized to identify a shading area and a solid model has complete, valid, and unambiguous spatial addressability. In addition, a lower-level model (i.e. a wireframe) can be extracted from a high-level surface or solid model. The same geometry can be modelled in different ways. However, it is desirable to take into consideration the design intents in geometric modelling. Design intent is beyond the size and shape of features and can be extended to manufacturing features such as tolerances, manufacturing processes, and design constraints. The use of design intents is an effective approach to build a parametric model of a part that is fully constrained and easy to mod- ify. By far, feature-based modelling is the most advanced method, where a part model is modelled as a set of features as well as their topological relations. Modern computer aided software tools support feature-based modelling methods.
eBook - PDFEngineering Design Graphics
Sketching, Modeling, and Visualization
- James M. Leake, Molly Hathaway Goldstein, Jacob L. Borgerson(Authors)
- 2022(Publication Date)
- Wiley(Publisher)
CHAPTER 1 276 10 CHAPTER ❚ INTRODUCTION Computer-Aided Design Computer-aided design (CAD) is a technology concerned with the use of computer-based tools employed by engineers, architects, and other design professionals in their design activities. CAD is used in the design of such artifacts as consumer products, tools, machinery, buildings, and infrastructure. Current applications include 2D drafting, Solid Modeling (both parametric and direct), surface modeling (both NURBS and freeform) and building information modeling (BIM). Although 2D drawing remains popular, CAD capabilities have developed well beyond the ability to generate drawings. Today’s model- based, object-oriented CAD programs provide designers, engineers, and architects with the ability to digitally capture a product’s or build- ing’s definition, and to integrate this definition into the knowledge base of the entire enterprise. The resulting digital product (or building) model can then be used to simulate the behavior of the design under varying conditions. Categories of CAD Systems In this section, 2D CAD, solid, parametric, direct, surface, and freeform modeling are briefly dis- cussed. Later in this chapter parametric Solid Modeling is discussed in greater detail. The chapter concludes with a discussion of cloud- based CAD. NURBS surface and freeform mod- eling are discussed in Chapter 11. COMPUTER-AIDED DRAWING In 1982 Autodesk launched AutoCAD ® , the first commercially successful 2D vector-based draft- ing program. Vector graphics employs geometric elements like points, lines, curves, and polygons to represent images. Since these elements are defined mathematically, they can be stored in a database and later manipulated (e.g., copied, moved, rotated, scaled, arrayed). 2D CAD is used by civil engineers, architects, land developers, interior designers, and other design professionals.
eBook - PDF- Alison Smith(Author)
- 2013(Publication Date)
- Butterworth-Heinemann(Publisher)
Recent developments in computer-aided design and engineering R M Sim Developments in CAD and CAE are described, with particu-lar reference to the area of solid modelling. This paper also outlines the efforts and successes (or otherwise) of some of the leading CAD companies. The need for standards and the problems inherent in their development are discussed. Finally, future trends in CAD are anticipated. computer technology, computer-aided design, computer-aided engineering Over the last two decades computer-aided design (CAD) has evolved into a reasonably stable tool that is well established in the marketplace. In the past year, however, there have been signs of significant upheavals in the industry caused mainly by the forces of rapid technological change. CAD equipment is now benefiting from the considerable advances being made in the semiconductor industry; what was done in software can now be done better and quicker in hard-ware. More advanced concepts are emerging and being incorporated in new devices. The advent of the personal computer (PC) and 32-bit workstations, and the use of net-works to link them together, are opening up a new environ-ment for the implementation of CAD techniques. At the same, time, manufacturing industry is striving to find ways to improve its competitiveness and one such way is to adopt CAD tools to help speed up the design process. Another way is to use computer-aided manufacturing (CAM) in the production process and to forge closer links between design and production by integrating CAD with CAM (CADCAM). Nowhere is this more evident than in the electronics industry where integrated computer-aided engineering (CAE) is proving to be an absolute necessity to satisfy the need for shortlived products. A more long-term solution is to implement computer integrated manu-facturing (CIM) where the normal CADCAM functions are linked to production, resources and financial control systems operating in real time.
- Yoseph Bar-Cohen(Author)
- 2018(Publication Date)
- CRC Press(Publisher)
2 Computer-Aided DesignNicholaos Bilalis and Emmanuel Maravelakis2.1 Introduction2.2 3D CAD Models and Downstream Applications2.3 Methods for Building the 3D Model2.4 Basics of Geometric and Solid Modeling2.4.1 Parametric Representation2.4.2 Bézier Curves2.4.3 B-Spline Curves2.4.4 Rational Bézier and B-Spline Curves (NURBS)2.4.5 Subdivision Curves and Surfaces2.5 Building the 3D Model2.5.1 Wireframe Modeling2.5.2 Surface Modeling2.5.3 Subdivision Modeling2.5.4 Reverse Engineering Modeling2.5.5 Parametric Feature-Based Solid/Surface Modeling2.5.6 Direct Modeling2.6 3D Product—Assembly Modeling2.7 PLM Systems and Collaborative Design2.8 Challenges in CAD Modeling2.9 ConclusionsAcknowledgment References2.1 IntroductionA computer-aided design (CAD) is considered the use of computer systems for the creation, modification, analysis, and optimization of a design (Groover and Zimmers, 1984, McMahon and Browne, 1998, Lee, 1999, Zeid, 2005). The technique was initiated at MIT by Ian Sutherland, when Sketchpad, the first system, was created within the Semi-Automatic Ground Environment research project in 1963. CAD systems were first introduced for the automation of two-dimensional (2D) drawings, but it soon became evident that 3D representation is essential, and today, the use of the 3D model is dominant in most industrial sectors driving all downstream applications. Early systems were based on the single-vendor systems with the concept of “turnkey” solutions, followed by the development of a wide range of systems and applications outside the concept of “turnkey” solutions while simultaneously advancing the data exchange between applications; today, through the introduction of Product Lifecycle Management (PLM) systems, a new type of “turnkey” solution is observed, driven by an extensive interoperability between systems and specialized applications.
eBook - ePub- D.V. Rosato, D.V. Rosato(Authors)
- 2003(Publication Date)
- Elsevier Science(Publisher)
Today’s software developers are laced with a serious challenge concerning how to produce a safe and reliable product in the shortest possible time frame. This is not a new problem; it has simply been exaggerated in recent years by pressures from the marketplace, and the manufacturing industry certainly is not immune to those pressures. Manufacturers including throwing large budgets into software development tools and manpower have sought many solutions.Geometric modeling
Geometric modeling is one of the major uses of the CAD systems. It uses mathematical descriptions of geometric elements to facilitate the representation and manipulation of graphical images on the computer’s screen. While the central processing unit (CPU) provides the ability to quickly make the calculations specific to the element, the software provides the instructions necessary for efficient transfer of information between user and the CPU.There are three types of commands used by the designer in CAD geometric modeling. Its first allows the user to input the variables needed by the computer to represent basic geometric elements such as points, lines, arcs, circles, splines, and ellipses. The second is used to transform these elements that include scaling, rotation, and translation. The third allows the various elements previously created by the first two commands to be joined into a desired shape. During the whole geometric modeling process, mathematical operations are at work that can be easily stored as computerized data and retrieved as needed for review, analysis, and modification.There are different ways of displaying the same data on the CRT (cathode ray tube) screen, depending on the needs or preferences of the designer. One method is to display the design as a 2-D representation of a flat object formed by interconnecting lines. Another method displays the design as a 3-D view of the product. In 3-D representations, there are the four types of modeling of wireframe modeling, surface modeling, Solid Modeling, and hybrid Solid Modeling.The wireframe model is a skeletal description of a 3-D part. It consists only of points, lines, and curves that describe the geometric boundaries of the object. There are no surfaces in a wireframe model. The 3-D wireframe representations can be confusing because all of the lines defining the object appear on the 2-D display screen. This makes it difficult for the viewer to tell whether the model is being viewed from above or below, inside or outside. It is the simplest of the CAD/CAM modeling methods. The simplicity of this modeling method also implies simplicity in the database.
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