Teaching CAD in Mechanical and Manufacturing Engineering Programs – An Experience at University of Calgary – D. Xue Department of Mechanical and Manufacturing Engineering, University of Calgary Calgary, Alberta, Canada T2N 1N4 E-mail: [email protected]

Abstract This paper introduces our experience of teaching a CAD course in mechanical and manufacturing engineering programs at University of Calgary. Three aspects of the CAD knowledge, including computer graphics theory, practice of CAD systems, and applications of CAD in engineering design and manufacturing, are discussed based on the requirements for the mechanical and manufacturing engineering programs. The various components of a CAD course at University of Calgary, including lectures, laboratories, textbooks, assignments, and course projects, are provided at the end of this paper.

1. Introduction Development of CAD tools was started by the pioneer work of the SKETCHPAD project at the MIT for designing an electronic drafting board to replace the conventional mechanical drafting board [1]. In 1970s, considerable theoretical results have been achieved in computer graphics, such as solid modeling, free form curve and surface modeling, and visualization of 3-D geometric objects. In 1980s, commercial CAD systems, such as AutoCAD by Autodesk for 2-D drafting and Pro/Engineer by Parametric Technology Corporation (PTC) for 3-D modeling, were introduced. Today CAD systems are widely used in engineering design and manufacturing, including geometric modeling, structure analysis, motion analysis, CNC machining, rapid prototyping, and so on. The CAD courses were introduced to mechanical and manufacturing engineering programs in 1980s with the advances of computer hardware and software technologies. Due to the limited functions of CAD systems in late 1980s and early 1990s, most of the efforts in these CAD courses were devoted to the CAD

theory, primarily computer graphics, for satisfying requirements in engineering design and manufacturing. Since many advanced functions, such as finite element analysis (FEA), motion analysis, CNC simulation and machining, and computational fluid dynamics (CFD), have been added to the CAD systems in the past decade, focus of teaching CAD courses has also been shifted from computer graphics to applications of CAD in engineering design and manufacturing. Presently CAD is considered as a fundamental component in mechanical and manufacturing engineering programs. CAD is usually introduced through the following three types of courses. • Junior undergraduate course in engineering graphics: to use a CAD system as an electronic drafting tool to practice engineering graphics knowledge. • Senior undergraduate course and junior graduate course in CAD/CAM/CAE: to use a CAD system as a tool for engineering design, manufacturing, and analysis. • Senior graduate course for special purposes: to use and to develop specialized CAD systems for complex shape modeling, customized finite element generation, computer animation, and so on. In recent years, the following questions are often raised due to the improvement of CAD functions. (1) Should a CAD course be offered in mechanical and manufacturing engineering programs? Two issues are usually considered to decide whether a course should be offered. First the topics in the course have to be essential for the program. Second the materials of the course take systematic approach to learn. For a good CAD system, it takes only days, if not hours, to learn the fundamental functions of 3-D modeling and 2-D drafting.

Therefore questions are raised on whether a CAD course should be offered. In other words, are we satisfied if the students have some fundamental knowledge on 3-D and 2-D geometric modeling? (2) What should be offered in a CAD course? Suppose we agree that a CAD course should be offered in the mechanical and manufacturing engineering programs as what has been well accepted by most present mechanical and manufacturing engineering programs, the questions on what should be offered are often raised. Should we focus on the CAD theory – the computer graphics? Should we introduce sophisticated functions of a CAD system? Or should we focus on the engineering applications of CAD systems? This paper aims at answering the above two questions by studying the three aspects of CAD knowledge required for the mechanical and manufacturing engineering programs. • CAD Theory – Computer Graphics • Practice of CAD Systems • Applications of CAD in Engineering Design and Manufacturing These three aspects of CAD knowledge are discussed with details in Sections 2.1, 2.2, and 2.3, respectively.

2. Three Aspects of CAD Knowledge For each aspect of CAD knowledge, we focus on the following two issues: • CAD Knowledge • Use of CAD Knowledge Manufacturing

in

Design

and

In addition, case study examples are also given to support our discussions. 2.1. CAD Theory in a CAD Course CAD theory, primarily computer graphics, serves as the foundation to develop CAD systems and to understand CAD concepts. Since the objective of a CAD course in mechanical and manufacturing engineering programs is not to implement new CAD systems, questions on whether computer graphics should be introduced or what topics in computer graphics should be introduced are often raised. 2.1.1. CAD Theory – Computer Graphics By studying the popular computer graphics and CAD textbooks [2-8], the major topics of computer graphics are grouped into the following categories.

• Hardware and Software − Input devices: keyboards, mice, digitizers − Output devices: monitors, raster printers, vector plotters − Computer systems: operating systems, programming languages, computer networks − Computer graphics tools: OpenGL, VRML [5,6] • 2-D Drafting − Primitives: lines, circles, arcs, ellipses, etc. − Area filling: solid filling, pattern filling − Clipping of 2-D primitives in views • 3-D Solid Modeling − Data structures: CSG, B-reps, half-space − Boolean operations: union, intersection, difference − Euler’s law • Geometric Transformation and Mapping − 2-D transformations: translation, rotation, etc. − 3-D transformations: translation, rotation, etc. − Mapping between two coordinate systems • 3-D Geometric Viewing − Projections: perspective projection, parallel projection − Windows, view ports, and their mapping • Modeling of Curves and Surfaces − Analytic curves: lines, circles, conics, etc. − Synthetic curves: Hermite cubic curves, Bezier curves, B-spline curves, NURBS curves − Analytic surfaces: planar surfaces, ruled surfaces, surfaces of revolution, tabulated cylinders − Synthetic surfaces: bicubic surfaces, Bezier surfaces, B-spline surfaces, NURBS surfaces • Detection of Visible Curves and Surfaces − Detection of visible curves − Detection of visible surfaces • Illumination and Shading − Color models: RGB, CMY − Light properties: diffuse reflection, specular reflection, ambient reflection − Shading models for polygons: constant shading, Gouraud shading − Transparency properties of materials − Shadows − Surface texture mapping • Computer Animation − Motion simulation − Virtual reality with sensor devices

2.1.2. Applications of CAD Theory in Design and Manufacturing Although a good understanding of computer graphics theory helps students to use CAD systems more effectively, considerable efforts are required to learn the topics in computer graphics. Since the objective of the CAD course in mechanical and manufacturing engineering programs is not to develop new CAD systems, some of the computer graphics topics may never have chances to be employed by engineering students in their future careers. In this section, the required computer graphics topics for a CAD course are identified by studying the relations between computer graphics topics and their applications in mechanical and manufacturing engineering. We classified these topics into three major categories, • Not Required • Concepts Only • In-depth Formulation as shown in Table 1. The major potential applications of the computer graphics knowledge in mechanical and manufacturing engineering are listed as follows. • Hardware and Software − Selection of computer systems (e.g., PC or Silicon Graphics workstations, MS Windows or UNIX) − Selection of input and output devices (e.g., mouse or digitizer, raster printer or vector plotter) − Selection of computer graphics tools for developing customized CAD systems when the required functions are not provided in existing CAD systems • 3-D Solid Modeling − More effective use of a CAD system by eliminating unnecessary geometric details to reduce the size of the CAD model • Geometric Transformation and Mapping − Identification of robot arm locations and CNC cutting paths − Mapping from the CAD coordinate system to the machine coordinate system in CNC • 3-D Geometric Viewing − Perspective projection for marketing − Parallel projection for engineering graphics • Modeling of Curves and Surfaces − Sculptured surface modeling using the data obtained through reverse engineering

Table 1. Selection of computer graphics topics Computer Graphics Topics Hardware and Software – Input devices – Output devices – Computer systems – Computer graphics tools 2-D Drafting – Primitives – Area filling – Clipping of 2-D primitives in views 3-D Solid Modeling – Data structures – Boolean operations – Euler’s law Geometric Transformation and Mapping – 2-D transformations – 3-D transformations – Mapping between two coordinate systems 3-D Geometric Viewing – Projections – Windows, view ports Modeling of Curves and Surfaces – Analytic curves – Synthetic curves – Analytic surfaces – Synthetic surfaces Detection of Visible Curves and Surfaces – Detection of visible curves – Detection of visible surfaces Illumination and Shading – Color models – Light properties – Shading models for polygons – Transparency properties of materials – Shadows – Surface texture mapping Computer Animation – Motion simulation – Virtual reality with sensor devices

N

C

I

X X X X X X X X X X X X X X X X X X X X X X X X X X X X X

N: Not Required C: Concepts Only I: In-depth Formulation

− Sculptured surface machining using 5-axis CNC machine • Illumination and Shading − Promotion of the design • Computer Animation − Robot motion simulation − Production system simulation 2.1.3. Case Studies Case Study 1: Application of Transformation A milling cutter moves first along a line (which starts from point A and ends at point B as shown in Fig. 1), and then moves along an arc (which starts from point B and ends at point C). Suppose point A is

located at A = [1,2]T. From point A, the cutter moves 2 units in x-axis direction and 1 unit in y-axis direction to point B. The center of the arc, D, is located at D = [6,3]T and the radius of this arc is 3. Obtain the matrices [T1] and [T2] for these transformation operations and calculate the coordinates of B and C using B = [T1]A C = [T2]B 6

C

Y

2.2. Practice of CAD Systems in a CAD Course Practice of CAD systems is considered as the core component in a CAD course. Two extreme opinions are often heard on how to teach CAD systems. • Since a CAD system is merely a computer software package, it can be learned by the students themselves. • Since a CAD system usually provides a very large number of functions, it is impossible to teach a CAD system. In this section, we first study the major functions of CAD systems. Then we discuss how these functions should be introduced in a CAD course.

4

B

2

2.2.1. Functions of CAD Systems Presently many CAD systems are available for engineering design and manufacturing. The major CAD systems are summarized in Table 2.

D

A

Table 2. Major CAD systems

O

X 4

2

6

Figure 1. CNC cutter path calculation

Case Study 2: Application of Surface Modeling Scoliosis is the abnormal spine curvature developed by children. A patient needs to wear a brace to prevent progression of the spine curvature. Since some patients have difficulty to find the braces with the right sizes and shapes, customized braces are required to be manufactured. Fig. 2 shows the process for customized brace design and manufacture. Since special algorithms are used to create the brace shape and the CNC machining codes to produce the male brace die, a customized CAD system has to be developed. Sculptured surface modeling functions of OpenGL [5] was employed in this project [9].

CAD System AutoCAD CATIA CoCreate I-DEAS Inventor IronCAD KeyCreator Pro/Engineer Solid Edge SolidWorks Think3

Company Autodesk Dassault CoCreate UGS Autodesk IronCAD Kubotek USA PTC UGS SolidWorks Think3

Web www.autodesk.com www.3ds.com www.cocreate.com www.ugs.com www.autodesk.com www.ironcad.com www.kubotekusa.com www.ptc.com www.ugs.com www.solidworks.com www.think3.com

The major functions of the CAD systems are summarized as follows. • 2-D Drafting − 2-D object creation: point, line, arc, circle, rectangle, spline, etc.

Camera

Frame

Patient’s Standing Location

(a) Obtain shape of the torso by a laser system

(b) Model shape of the brace based on the shape of the torso

(c) Create brace male die using 5axis CNC machining

Figure 2. Process of customized brace design and manufacture

− 2-D object manipulation: mirror, fillet, chamfer, offset, trim, extend, etc. − Projection views: top view, front view, right view, isometric view, auxiliary view, detail view, crop view, broken-out view, section view − Dimensions: linear dimension, radial dimension, angular dimension − Annotations: note, balloon, datum, surface finish, tolerance, center mark − Title box and bill of materials • 3-D Modeling − Primitives: block, cylinder, cone, wedge, sphere, torus − Sweeping: translational sweeping, rotational sweeping − Boolean operations: union, intersection, difference − Parametric modeling: linear dimension, radial dimension, angular dimension − Variational geometry: parallel, perpendicular, tangent, collinear, concentric − Assembly modeling: coincident, parallel, perpendicular, distance, angle, concentric, tangent • Visualization − Viewing: wireframe, hidden line visible, hidden line removed, shaded, pan, rotation, zoom in, zoom out − Illumination: color of part, material of part, transparency property of part, lights, texture of surface − Animation: explosion of parts in an assembly, changes of positions and orientations of parts, kinematics motion •

Management of Geometric Objects − Dependency relations among geometric elements (e.g., features) − Different configurations of the same part and assembly

• Design Libraries − User defined features − Standard parts: bolts, nuts, gears, etc. • Data Exchange − Import/export of files from/to other CAD systems − CAD data exchange standards: IGES, STEP − Extraction of features from geometry • Product Data Management − Permissions and preemptions of file access − Management of files in a large CAD project

• Collaboration − Data sharing through Internet and Web − Collaboration and coordination among team members distributed at different locations • Customized CAD Systems − Systems developed using solid modeling kernels: ACIS, Proprietary, Parasolid − Add-in modules of existing CAD systems: C++ based ObjectARX for AutoCAD, C++ based Pro/Tookit for Pro/Engineer, C++ based API for SolidWorks − Systems developed using common computer graphics libraries: OpenGL, Java3D In addition to geometric modeling, CAD systems also provide functions to support various design and other product development activities, such as design optimization, finite element analysis, motion analysis, computational fluid dynamics analysis, tolerance analysis, mold design, CNC machining, rapid prototyping, reverse engineering, and son on. These engineering applications are discussed in Section 2.3. 2.2.2. Practice of CAD Functions Different efforts are required to practice different functions of CAD systems. We classify these CAD functions into the following 3 major categories, • Optional Functions • Fundamental Functions • Core Functions based on the potential of using these CAD functions in engineering design and manufacturing as shown in Table 3. 2.2.3. Case Studies Two case studies to develop customized CAD systems are introduced in this section. Case Study 1: An Add-in Module of SolidWorks An add-in module to create the geometry of a block was developed using SolidWorks C++ API functions. When the three parameters of a block, as shown in Fig. 3 (a), are entered, the geometry of the block, shown in Fig. 3 (b), is then created automatically using the SolidWorks API functions. Similar method can be employed to implement a bookshelf design system by entering the following parameters. • • • • •

height width depth number of shelves color

Table 3. Selection of CAD functions CAD Functions 2-D Drafting 2-D object creation 2-D object manipulation Projection views Dimensions Annotations Title box and bill of materials 3-D Modeling Primitives Sweeping Boolean operations Parametric modeling Variational geometry Assembly modeling Visualization Viewing Illumination Animation Management of Geometric Objects Dependency relations Different configurations Design Libraries User defined features Standard parts Data Exchange Import and export of files CAD data exchange standards Extraction of features Product Data Management Permissions and preemptions of file access Management of large CAD project Collaboration Data sharing through Internet and Web Distributed collaboration and coordination Customized CAD Systems Using solid modeling kernels Add-in modules of existing CAD systems Using common computer graphics libraries

O

F

C X X X X

X X

(a). A dialog box for entering parameters X X X X

X X X X X X X

(b). Automatically created geometry X X X X X X X X X X X X

O: Optional Function F: Fundamental Function C: Core Function

Figure 3. An add-in module of SolidWorks

GLint nMumberPoints = 3; // control point number GLfloat ctrlPoints[3][3][3] = {{{-4.0f, 0.0f, 4.0f}, {-2.0f, 4.0f, 4.0f}, {4.0f, 0.0f, 4.0f}}, {{-4.0f, 0.0f, 0.0f}, {-2.0f, 4.0f, 0.0f}, {4.0f, 0.0f, 0.0f}}, {{-4.0f, 0.0f, -4.0f}, {-2.0f, 4.0f, -4.0f}, {4.0f, 0.0f, -4.0f}}}; glMap2f(GL_MAP2_VERTEX_3, // Bezier surface type 0.0f, // lower u range 10.0f, upper u range 3, // distance between points in the data 3, // dimension in u direction (order) 0.0f, // lower v range 10.0f, upper v range 9, // distance between points in the data 3, // dimension in v direction (order) &ctrlPoints[0][0][0]); //pointer to the control point array glEnable(GL_MAP2_VERTEX_3); (a). C++ program

Case Study 2: Surface Modeling Using OpenGL A Bezier surface with 3 × 3 control points is modeled using the C++ functions of OpenGL [5]. Part of the C++ program and the created Bezier surface are shown in Fig. 4 (a) and (b), respectively. The scoliosis brace design and manufacturing system introduced in Section 2.1.3 (see Fig. 2) was also developed by OpenGL to model the surfaces using NURBS functions [9]. 2.3. Engineering Applications in a CAD Course The goal of learning CAD is to solve engineering design and manufacturing problems using the CAD knowledge.

(b). Created Bezier surface Figure 4. Modeling of a Bezier surface using OpenGL

2.3.1. Engineering Applications of CAD In addition to geometric modeling, CAD systems are used throughout various life-cycle phases of product development. We classify the CAD applications into the following major categories.

Table 4. Selection of CAD applications CAD Applications Finite Element Analysis Motion Analysis Computational Fluid Dynamics Analysis Optimization CNC Simulation and Machining Mold Design Rapid Prototyping Reverse Engineering Virtual Reality

• Finite Element Analysis (FEA) − Structure analysis: stresses, strains, displacements − Thermo analysis: temperatures, heat fluxes • Motion Analysis − Mechanism design: joints, initial conditions − Simulation and animation: positions, velocities, accelerations • Computational Fluid Dynamics (CFD) Analysis − External and internal flows − Steady-state and transient flows − Incompressible liquid and compressible gas flows • Optimization − Design parameters, objective function, search methods • CNC Simulation and Machining − Modeling of manufacturing geometry − Creation of machining paths − Simulation of machining processes • Mold Design − Creation of mold geometry − Selection of parting lines

O

C

P X X

X X X X X X X

O: Optional C: Concepts/Demos Only P: Practice Required

2.3.3. Case Studies Two case studies for structure analysis and motion analysis are introduced in this section. Case Study 1: Structure Analysis with COSMOSWorks COSMOSWorks is the add-in module of SolidWorks for finite element analysis. A COSMOSWorks structure analysis tutorial used in our CAD course is shown in Fig. 5. The boundary conditions are defined as: • • • • •

Analysis type: static analysis Material: alloy steel Mesh type: solid mesh Restraint type: immovable surfaces of two holes Pressure: 1000 psi normal to a planner surface

• Rapid Prototyping − Creation of STL files − Consideration of support structures • Reverse Engineering − Data acquisition methods: CMM, laser scanning • Virtual Reality − Devices: head mounted display, haptic devices, data gloves

(a). Boundary conditions

2.3.2. Selection of CAD Applications Different efforts are required to introduce and practice different CAD applications. We classify these CAD applications into the following 3 major categories, • Optional • Concepts/Demos Only • Practice Required based on the potential of using these applications in engineering design and manufacturing as shown in Table 4.

(b). Result of stress distribution Figure 5. Structure analysis with COSMOSWorks

Case Study 2: Motion Analysis with COSMOSMotion COSMOSMotion is the add-in module of SolidWorks for motion analysis. A COSMOSMotion motion analysis tutorial used in our CAD course is shown in Fig. 6. This mechanism is used to transform the rotational motion of the driver part to the linear motion of the driven part. This mechanism is defined by 9 joints as shown in Fig. 6 (a). The angular displacement of the driver part is defined as

θ = 2πt , 0 ≤ t ≤ 1 where t is the timing parameter in unit of second. The acceleration parameter of the driven part can be achieved by motion analysis as shown in Fig. 6 (b).

Driven Part

Driver Part (a). A mechanism with joint constraints

(b). Acceleration of the driven part Figure 6. Motion analysis with COSMOSMotion

3. The CAD Course at University of Calgary Based upon the discussions given in Section 2, we can answer the two questions raised in Section 1. • A CAD course should be offered in the mechanical and manufacturing engineering programs, since many topics in the three aspects of CAD knowledge (i.e., computer graphics, CAD systems, applications of CAD) are used in engineering design and manufacturing. • For each aspect of the CAD knowledge, only the topics that have potential engineering applications should be selected in the CAD course.

Based on the above considerations, a CAD course, ENMF 401, for mechanical and manufacturing engineering programs at University of Calgary was designed as a senior undergraduate course with the following course components. 3.1. Lectures Lecture sessions are used for introducing CAD concepts and CAD systems. SolidWorks and its add-in modules (COSMOSWorks and COSMOSMotion) are used for this course. Organization of the lectures is given in Table 5. Table 5. Lectures of the CAD course Introduction Components of CAD Systems Hardware Components − Input Devices − Output Devices Software Components − Functions of CAD Systems − Major CAD Systems Geometric Modeling Wireframe Models, Surface Models, and Solid Models 3-D Solid Modeling Functions CAD Data Structures − Constructive Solid Geometry (CSG) Model − Boundary Representation (B-rep) Model Geometric Transformation, Viewing, and Visualization 2-D and 3-D Geometric Transformations Geometric Viewing − Orthographic Projections − Perspective Projections Visualization − Color Models − Shading Complex Shape Modeling Analytic and Synthetic Representations of Curves Analytic and Synthetic Representations of Surfaces Computer-aided Machine Component Design Applications of CAD in Product Development Motion Analysis Structure Analysis Tolerance Analysis and Synthesis Design Optimization CNC Simulation and Machining Rapid Prototyping 3-D Geometric Data Acquisition and Reverse Engineering Virtual Engineering Standards for Communicating between Systems Advanced Topics on CAD CAD Systems SolidWorks COSMOSWorks COSMOSMotion

3.2. Laboratories Laboratory sessions are used for practicing functions of the CAD systems including SolidWorks,

COSMOSWorks, and COSMOSMotion. laboratories are summarized in Table 6.

These

Table 6. Laboratories of the CAD course Laboratory Laboratory 1 Laboratory 2 Laboratory 3 Laboratory 4 Laboratory 5 Laboratory 6 Laboratory 7 Laboratory 8

Topics Part Modeling in SolidWorks Assembly Modeling in SolidWorks Drawing Modeling in SolidWorks Complex Shape Modeling in SolidWorks Visualization Functions in SolidWorks Other Advanced SolidWorks Functions Structure Analysis with COSMOSWorks Motion Analysis with COSMOSMotion

• Students are encouraged to use advanced functions of the SolidWorks, including complex curves and surfaces, constraints, visualization functions, crosssections, different types of views such as detailed views, auxiliary views, revolving views, partial views, and so on, to model the parts, assemblies, and drawings. • Students are required to use either COSMOSWorks or COSMOSMotion, or both of them for the structure analysis and the motion analysis.

3.3. Textbook and Reference Books • Textbook: Lee, K., 1999, Principles CAD/CAM/CAE, Addison-Wesley.

of

• Major Reference Book: Zeid, I., 1991, CAD/CAM Theory and Practice, McGraw-Hill. • Other Reference Books: [2-5] 3.4. Assignments CAD assignments and written assignments are given for practicing the knowledge learned in the laboratories and lectures. These assignments are summarized in Table 7. Table 7. Assignments of the CAD course Assignment CAD 1 CAD 2 Written 1 Written 2

• For each of the important components, a 2-D drawing with appropriate views is required. All dimensions and necessary tolerances should be given in the 2-D drawings.

Topics Part Modeling, Assembly Modeling, and Drawing Complex Shape Modeling, Visualization, and Other CAD Functions Geometric Modeling and Transformation All Other CAD Topics

3.5. Final Course Project The final course project focuses on design and analysis of a product with a number of components using SolidWorks and its add-in modules including COSMOSWorks and COSMOSMotion. The requirements of the final course project are given as follows. • For each non-standard component, a SolidWorks part should be created to model this component. • The whole product should be created as a SolidWorks assembly. • A 2-D drawing is required for the product assembly. A balloon with a part ID number is required to label each component in the assembly. Bill of materials and a title box are also required for the assembly drawing.

Each final course project is evaluated by a proposal, a report, and a presentation. Some of the completed final course projects are given in Fig. 7. 3.6. Course Evaluation The performance of students is evaluated by assignments, a final course project, a mid-term examination, and a final examination. The evaluation scheme is summarized in Table 8. Table 8. Grading of the CAD course Course Component CAD Assignment 1 CAD Assignment 2 Written Assignment 1 Written Assignment 2 Final Course Project Proposal Final Course Project Presentation Final Course Project Report Midterm Examination Final Examination TOTAL

Percentage 9% 6% 5% 5% 1% 3% 16% 15% 40% 100%

4. Summary Our experience of teaching a CAD course for mechanical and manufacturing engineering programs at University of Calgary is summarized as follows. 1. Computer graphics serves as the theoretical foundation of CAD. Many computer graphics topics, such as geometric transformations and free form curve/surface modeling, have potential to be used in engineering design and manufacturing. 2. Practice of CAD systems is a core component of a CAD course. In addition to the fundamental functions of CAD including 3-D modeling, 2-D drafting and assembly modeling, other functions, such as visualization, geometric object management, use of design libraries, data

(a). A front suspension mechanism

(b). An oil pump

(c). A shovel excavator

(d). A steering system

(e). A recumbent bicycle

(f). A hydraulic trolley jack

Figure 7. Samples of completed final course projects

exchange, and development of customized CAD systems, should also be introduced. 3. Application of the CAD knowledge for solving engineering design and manufacturing problems is the goal of the CAD course. Students need to understand the relations between CAD and other courses in the mechanical and manufacturing engineer programs. Students also need to practice the fundamental application functions, such as finite element analysis and motion analysis, in the CAD course.

References [1] I. E. Sutherland, “SKETCHPAD: A Man-Machine Graphical Communication System,” Spring Joint Computer Conference, Baltimore, MD, 1963.

[2] J. D. Foley, A. van Dam, S. K. Feiner, and J. F. Hughes, Computer Graphics: Principles and Practice, AddisonWesley, 1990. [3] J. D. Foley, A. van Dam, S. K. Feiner, and J. F. Hughes, Computer Graphics: Principles and Practice in C, Addison-Wesley, 1995. [4] D. Hearn and M. P. Baker, Computer Graphics: C Version, Prentice Hall, 1997. [5] D. Hearn and M. P. Baker, Computer Graphics with OpenGL, Prentice Hall, 2003. [6] A. L. Ames, D. R. Nadeau and J. L. Moreland, VRML 2.0 Sourcebook, John Wiley & Sons, 1996. [7] I. Zeid, CAD/CAM Theory and Practice, McGraw-Hill, 1991. [8] K. Lee, Principles of CAD/CAM/CAE, Addison-Wesley, 1999. [9] Wu, H., et al., "Design and Manufacturing of Customized Braces for Scoliosis Treatment," Proceedings of the 2002 ASME Design Engineering Technical Conference, Montreal, Quebec, 2002.