VALLIAMMAI ENGINEERING COLLEGE

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VALLIAMMAI ENGINEERING COLLEGE SRM Nagar, Kattankulathur 603 203 DEPARTMENT OF MECHANICAL ENGINEERING QUESTION BANK M.

1 VALLIAMMAI ENGINEERING COLLEGE SRM Nagar, Kattankulathur DEPARTMENT OF MECHANICAL ENGINEERING QUESTION BANK M.E: CAD/CAM I SEMESTER ED5151 COMPUTER APPLICATIONS IN DESIGN Regulation 2017 Academic Year Prepared by Dr.S.Thirugnanam, Professor Mr.R.Ram Kumar, Assistant Professor

2 UNIT-I INTRODUCTION TO COMPUTER GRAPHICS FUNDAMENTALS Output primitives (points, lines, curves etc.,), 2-D & 3-D transformation (Translation, scaling, rotation) windowing - view ports - clipping transformation. PART-A (2 marks) S.No QUESTIONS BT Level Competence 1. Define persistence BT1 Remember 2. Quote the term resolution BT1 Remember 3. Define aspect ratio BT1 Remember 4. Express the term frame buffer or refresh buffer BT2 5. Contrast the terms pixel, bitmap and pixmap. BT2. 6. Label the term output primitives. BT1 Remember 7. Deduce the techniques used in colour CRT monitors. BT5 Evaluate 8. List the line drawing algorithms used in scan conversions. BT1 Remember 9. Compare analog flat panel displays and digital flat panel displays. 10. Point out how flat screen CRT varies from curved CRT. BT3 Apply 11. Differentiate between regular CRTs and flat screen CRTs. BT2 12. Compare DDA algorithm with Brenham s algorithm 13. For the position vectors P 1 [2, 3] and P 2 [4, 5]determine the parametric representation of the line segment between them BT5 Evaluate 14. Illustrate the Scan-conversion process of a straight line in terms of pixel position BT3 Apply 15. Explain what happens to the picture that are too large to fit in the screen? BT6 Create 16. List the limitations of a CAD software. BT1 Remember 17. Classify geometric transformations. BT3 Apply 18. Define translations. BT6 Create 19. Define scaling transformation BT2 20. Classify clipping transformation. PART-B (13 marks) 1. Describe principle and working of CRT with the aid of neat sketch. BT1 Remember 2. Summarize any 10 parameters that are used in CRTs BT2 3. Write short notes on the analog flat panel displays BT3 Apply

3 4. Rotate the triangle ABC counterclockwise by 30, where the triangle has coordinates A(1,1), B(3,1) and C (1,3). BT5 Evaluate 5. Describe about the 3 D translation and 3 D rotation. BT1 Remember 6. Translate a triangle ABC with coordinates A (1, 1), B (5,2), C (3,3) about the origin by 3 units in the x-direction and 2 units in the y- 7. direction. Scale the polygon ABCD with vertices A(5,7) B(12,9) C(10,15) D(7,16) by Create 2 units in X direction & 3 units in Y direction by keeping the vertices D as BT6 fixed. 8. Explain the working of Digitizers and Image scanners 9. Identify and describe the reasons for implementing a computer aided Remember design system BT1 10. Explain how an image is generated and maintained in a direct beam refresh terminal. 11. Explain the working of CPU BT3 Apply 12. Elaborate on the basic requirements that a CAD software has to satisfy. BT2 13. Discuss the working of the digital flat panel displays. BT2 14. Describe about the reflection. BT1 Remember PART-C (15 marks) 1. Enumerate on the various types of the output primitives. BT1 Remember 2. Write notes on Homogenous Transformation Matrices, Digital differential BT2 analyzer and algorithm. 3. Explain the various types of mapping of the geometric models. BT3 Apply 4. Consider the line of coordinates (1,1) and (2,4) rotate the line about the origin Determine the transformation of the line. UNIT-II CURVES AND SURFACES MODELLING Introduction to curves - Analytical curves: line, circle and conics synthetic curves: Hermite cubic spline- Bezier curve and B-Spline curve curve manipulations. Introduction to surfaces - Analytical surfaces: Plane surface, ruled surface, surface of revolution and tabulated cylinder synthetic surfaces: Hermite bicubic surface- Bezier surface and B-Spline surface- surface manipulations. PART A (2 marks) 1. Write the parametric equation of a plane surface defined by three points P 0, P 1 and P 2 BT2 2. Write the explicit non parametric representations of a curve. BT2 3. Mention the limitations of the non-parametric representations of a curve BT3 Apply 4. Differentiate between analytical curves and synthetic curves. 5. Define Bezier curves. BT1 Remember

4 6. Differentiate between the beizer curve and cubic spline curve. BT2 7. Mention the requirements of curves and surface design. 8. List the features of the curve manipulations. 9. Define segmentation. BT1 Remember 10. Point out the types of surfaces. BT5 Evaluate 11. Quote the expression for the surface representation. BT1 Remember 12. Define patch. BT1 Remember 13. Differentiate between analytical surfaces and synthetic surfaces. BT2 14. List the applications of trimming in surface entities. BT3 Apply 15. Write the examples of prismatic and revolved parts. BT3 Apply 16. Differentiate between Bezier surfaces and hermite cubic surfaces. BT5 Evaluate 17. Mention the advantages of B-spline surfaces over the Bezier s surfaces. BT6 Create 18. Mention the methods of defining points. BT6 Create 19. List the methods of defining circles. BT1 Remember 20. State the methods of defining ellipses and parabolas. BT1 Remember PART-B (13 marks) 1. Explain any two features of the surface manipulations. BT1 Remember 2. Explain the various types of surface entities. BT1 Remember 3. Briefly explain about the plane surfaces. BT1 Remember 4. CAD/CAM systems use parametric representation for surfaces as they do for Curves. Explain how a surfaces is represented. 5. Sketch the geometric parameters required to create the following surface Apply Operations: 1).Tabulated cylinder 2). Revolve 3). Sweep 4). loft BT3 6. Sketch the geometric parameters required to define a helix. BT2 7. Determine the equation of the plane that passes through points P o (1,2,3), P 1 (3,4,-1) and P 2 (1,-2,2). Find the coordinates of the center point of the plane. Find the tangent vectors and the normal vector at this point. BT3 Apply 8. Elaborate the curve generation techniques. BT1 Remember 9. Summarize the characteristics of a Bezier curve. BT2 10. Summarize the characteristics of a B-spline curve. BT2 11. Explain the necessity of surface analysis. 12. Derive the expression for [M H ] T for a hermite cubic spline. 13. Derive the vector parametric equations of a straight line for a line connecting two end points. BT5 Evaluate

5 14. Derive the vector parametric equations of a straight line passing through a point P 1 in a direction defined by a unit vectorn. PART-C (15 marks) 1. Find the shape of cubic spline curve if the result is (i) P o = P 1,P 1 =P o ii) P o = P 1, P 1 = -P o BT6 Create 2. Discuss the various features of the curve manipulations. BT3 Apply 3. Explain about the Bezier curves. BT2 4. Discuss the representations of the curve and obtain its parametric equation. BT1 Remember UNIT III NURBS AND SOLID MODELING NURBS- Basics- curves, lines, arcs, circle and bi linear surface. Regularized Boolean set operations - primitive instancing - sweep representations - boundary representations constructive solid Geometry - comparison of representations - user interface for solid modeling. PART-A (2marks) 1. Define NURBS. BT1 Remember 2. List the advantages of NURBS. BT3 Apply 3. Define geometry BT1 Remember 4. Define topology BT1 Remember 5. Write the expression for NURB arc equation. BT6 Create 6. Mention the divisions of B-spline curves. BT3 Apply 7. Differentiate between rational and non-rational B-spline curves. 8. Define open knot vectors. BT1 Remember 9. Distinguish between valid solid and complete solid. BT2 10. Differentiate between boss and cut command. BT2 11. Define unambiguous solid. BT1 Remember 12. Sketch some non-uniqueness of solid models. BT5 Evaluate 13. Mention some commonly used solid primitives BT3 Apply 14. Distinguish between finiteness and finite describability. BT2 15. Quote the term non sense model BT1 Remember 16. Differentiate between closed surface and orientable surface. BT2 17. List the limitations of half-spaces. BT5 Evaluate 18. State the expression for Euler equations in B-rep. BT6 Create 19. Mention the types of sweeps. 20. Point out the building blocks of B-rep.

(iii) Objects with holes that do not go through the 3. entire Sketch object. the following (iv) Objects feature have operations holes that using go through CSG. entire objects.

6 PART-B (13 marks) 1. Summarize the steps involved to NURBS equation of a curve. BT2 2. Explain the following polyhedral object using B-rep elements and verify the Euler equation for the same (i) Simple Polyhedra. (ii) Polyhedral object a face may have loops. (iii) Objects with holes that do not go through the 3. entire Sketch object. the following (iv) Objects feature have operations holes that using go through CSG. entire objects. (i) Extruded (ii) Revolved feature (iii) Chamber (iv) Loft feature (v) Pocket (vi) Shell (vii) Fillet (viii) Draft (ix) Rib and (x) Dimple. BT5 BT6 Evaluate Create 4. List the differences and the similarities between nonlinear sweeps and lofts BT2 5. Write short notes on the various solid entities. BT1 Remember 6. Summarize the mathematical properties of a solid model. BT2 7. Point out the design applications of a CSG tree. 8. Explain the features of the solid manipulations. BT1 Remember 9. Discuss the various types of the sweep representations. 10. Sketch the CSG tree for the solids shown below. BT3 Apply 11. Check the validity of 3D solids. BT3 Apply

7 12. Verify the Euler equation for the following solids and check the validity of 3D solids 13. Write short notes on the curved and faceted B-rep models. BT1 Remember 14. Describe about the surface/surface intersection. BT1 Remember PART-C (15 marks) 1. Write notes on Boundary representation method and 2. Constructive Explain about Solid the NURBS Geometry and their necessity. BT2 BT1 Remember 3. Write notes on Boolean set of operations and Primitive instancing. BT3 Apply 4. Develop the NURB equation for a circle. UNIT-IV VISUAL REALISM Hidden Line Surface solid removal algorithms shading coloring. Introduction to parametric and variation geometry based software s and their principles creation of prismatic and lofted parts using these packages. PART-A (2marks) 1. List the various hidden line algorithm. BT1 Remember 2. Identify the algorithms used for hidden surface removal. BT1 Remember 3. Differentiate between raster algorithm and vector algorithm. BT2 4. Classify the removal algorithms. BT1 Remember 5. Mention few visibility techniques. BT3 Apply 6. List the parameters used for visibility of object views. BT2 7. Write the plan equation for surface test. BT1 Remember 8. Define Silhouette edges. BT1 Remember 9. List the types of coherence identified in object space and image space. BT6 Create 10. State the necessity of hidden surface algorithms. BT6 Create 11. How does edge coherence help to reduce computational effort? 12. Infer how does the basic scan line method determine which surfaces are 13. hidden? Interpret how does area coherence help to reduce computational effort? BT2 14. Evaluate how is spatial coherence determined? BT5 Evaluate

8 15. Explain why is it easier to locate hidden surfaces when parallel projection is needed? 16. Define Coherence. BT1 Remember 17. Mention the uses of homogeneity test. BT5 Evaluate 18. List the shading algorithms BT3 Apply 19. Mention the benefits of shading enhancements. BT3 Apply 20. Differentiate between RGB model and CMY color model. BT2 PART-B (13 marks) 1. Explain the method of back face removal. Give its advantages and limitations with reference to hidden line removal. BT2 2. Write short notes on visibility of the object views. BT2 3. Write short notes on a.) Minimax test b.) containment test BT1 Remember 4. Explain in detail about the various types of coherence. 5. Summarize the steps involved in the priority algorithm. BT2 6. Describe the procedures followed in area oriented algorithm for hidden line Evaluate removal. BT5 7. Explain the methods or the algorithms that are deployed for the Apply BT3 8. hidden Discuss solid the effects removal. of shading enhancements in the visualization. BT3 Apply 9. Explain the algorithms used for shading of solids. 10. Describe about the characteristics of the various color models. BT1 Remember 11. Write short notes on a.) Surface test b.) Computing silhouettes. BT1 Remember 12. How will you formulate and implement a technique for the hidden line BT6 Create removal. 13. Describe about a.) Z-buffer algorithm b.) Warnock s algorithm. BT1 Remember 14. What is lofted parts? Explain how are they created? PART-C (15 marks) 1. Explain briefly with sketches any six tests used for hidden line 2. identification. Discuss the various steps involved in hidden line removal algorithms BT1 Remember 3. with Explain neat the sketches. procedures and implementation of the ray tracing algorithm. BT3 Apply BT2 4. Elaborate on the shading and brief their impact on visual realism. UNIT-V-ASSEMBLY OF PARTS AND PRODUCT DATA EXCHANGE Assembly modeling - interferences of positions and orientation - tolerances analysis mass Property calculations - mechanism simulation. Graphics and computing standards Open GL Data Exchange standards IGES, STEP etc Communication standards.

9 PART-A (2marks) 1. Identify the elements of assembly analysis. BT1 Remember 2. Define assembly tree. BT1 Remember 3. List the various mating conditions. BT1 Remember 4. Mention the difference between the tangent and coincident mating 5. condition. Differentiate between WCS method and mate method. 6. Assess the steps involved in assembly analysis. BT5 Evaluate 7. Define tolerance analysis. BT1 Remember 8. Deduce the objective of tolerance analysis. BT5 Evaluate 9. Mention the uses of form tolerances. BT3 Apply 10. Sketch the ANSI symbol for straightness and flatness. BT6 Create 11. Sketch the ANSI symbol for position and angularity. BT6 Create 12. Classify the types of geometric tolerances. BT3 Apply 13. Define datum. BT1 Remember 14. Indicate the difference between mass property and geometric property. 15. Expand IGES and STEP. BT2 16. Interpret the methods of verification of processors. BT2 17. Differentiate between loopback test and transmission test. BT2 18. Examine the need for tolerances. BT3 Apply 19. List the various methods of tolerance synthesis. BT1 Remember 20. Interpret the three layers used in STEP architecture. BT2 PART-B (13 marks) 1. Explain the worst case arithmetic method for tolerance analysis. BT1 Remember 2. Discuss the worst case statistical method for tolerance analysis. BT1 Remember 3. Discuss how the surface area and first moment of inertia is 4. calculated Label the various using CAD ANSI software. from tolerances with neat diagram. BT2 BT1 Remember 5. Elaborate the various mating conditions for an assembly. BT3 Apply 6. Express IGES file structure with examples. BT2 7. Enumerate the concept of product data exchange using STEP in detail BT2

8. Use the bottom-up approach to create the model of the universal joint shown in Figure. BT5 Evaluate 9. The figure below shows a pin and a block with their MCSs.

Write short notes on assembly planning and mention the issues arising Apply 11. during Explain assembly. the steps involved during the modelling of the assembly. 12. Discuss the need for tolerances.

10 8. Use the bottom-up approach to create the model of the universal joint shown in Figure. BT5 Evaluate 9. The figure below shows a pin and a block with their MCSs. The pin and the instances to be assembled into the hole in the block. Use WCS and write the transformation matrices to merge the three instances of B into A. BT6 Create 10. Write short notes on assembly planning and mention the issues arising Apply 11. during Explain assembly. the steps involved during the modelling of the assembly. 12. Discuss the need for tolerances. 13. Collect the steps involved in the Monte Carlo simulation method. BT1 Remember 14. in detail about the Tolerance Vs Cost relationship. PART-C (15 marks) 1. Explain with the help of an example the concept of interferences of 2. positions Elaborate and on the orientation various methods by which of the the parts tolerance are assembled. analysis BT3 Apply BT2 3. Derive the expression for any 4 parameters of the mass properties. 4. Describe the architecture, file format of the various product data exchange standards. BT1 Remember

ME COMPUTER AIDED DESIGN COMPUTER AIDED DESIGN 2 MARKS Q&A

ME COMPUTER AIDED DESIGN COMPUTER AIDED DESIGN 2 MARKS Q&A ME6501 - COMPUTER AIDED DESIGN COMPUTER AIDED DESIGN 2 MARKS Q&A Unit I 1. What is CAD? Computer aided design (CAD) is the technology concerned with the use of computer systems to assist the creation,