Seat No.: ________ Enrolment No.
___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER– VI (NEW) EXAMINATION – WINTER 2021
Subject Code:3162006 Date:02/12/2021
Subject Name:Computer Aided Design and Modeling
Time:10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
4. Simple and non-programmable scientific calculators are allowed.
Q.1 (a) Write down the application of CAD system. 03
(b) State the applications of CAD in engineering giving suitable examples. 04
(c) State the most appropriate computer modeling system for: 07
Producing drawings and manufacturing data for flame-cut plates for
fabricated structure
Modeling automobile body panels
Visualization of the motion of a robot arm.
State reasons for your choices
Q.2 (a) Write the salient features of a good CAD software 03
(b) “Although vector scan displays have very high resolution, the raster scan displays 04
are very popular.” - Explain.
(c) A line joining points P (15, 17) and Q (22, 20) pixels is to be drawn using 07
Bresenham’s algorithm. Find the coordinates of intermediate pixels staring from
point P.
OR
(c) Differentiate between: 07
I. Raster scan display and random scan display
II. CRT display and LCD display
Q.3 (a) Discuss the need for standardization in computer graphics. 03
(b) Determine the resultant vertex positions of the triangle ABC having co-ordinates 04
A (10, 12), B (10, 22) and C (20, 22) that undergoes following transformations in
sequence.
i. Scaling with scale factor of 0.5 in both axes.
ii. Rotation by 90o clockwise about vertex A.
(c) A generalized parametric representation of Hermite Cubic spline is: 07
P(u) = (2u3-3u2+1)P0 + (-2u3+3u2)P1 + (u3-2u2+ u)P0’ + (u3- u2)P1’
Prove that the blending functions of the Hermite cubic spline curve are symmetric.
What is the consequence of this symmetry?
OR
Q.3 (a) Explain the following types of surfaces: Ruled surface, tabulated surface and 03
revolved surface
(b) The vertices of a triangle are located at points (15, 30), (25, 35) and (5, 45). Find 04
the coordinates of the vertices if the triangle is first rotated 150 in CCW direction
and then scaled to twice its size.
(c) A cubic Bezier spline is defined by the control points as (20, 20), (60, 80), (120, 07
100) and (150, 30) respectively. Find the equation of the curve and its mid-point.
Q-4 (a) What are the differences amongst wire frame, surface and solid models? What are 03
their typical applications?
1
(b) A point P is translated by (4, 2, 0), rotated about Z axis by 45º CCW and then 04
rotated about X axis by 30º CCW. Obtain the concatenated homogeneous
transformation matrix.
(c) Bezier curve is defined by four control points in sequence (3, 0, 1), (4, 0, 4), (8, 0, 07
4) and (10, 0, 1). Find the equation of the curve. Evaluate the function for u=0, 0.2,
0.4, 0.6, 0.8 and 1.0 and plot the curve.
OR
Q.4 (a) What is graphic standard? Explain different CAD standards. 03
(b) Take two solid objects of your choices and with help of neat diagrams, explain 04
various Boolean 2D and 3D operations.
(c) State and explain the continuity conditions in synthetic curves. 07
Q.5 (a) What is GKS and PHIGS? 03
(b) Explain the following terms used in optimization: 04
1. Design vector
2. Design constrains
3. Objective function
(c) Explain the graphical representation of design constrains. 07
OR
Q.5 (a) What is optimization? Explain it. 03
(b) State the application of optimization in engineering. 04
(c) A manufacturing firm produces two machine parts using lathes, milling machines 07
and grinding machines. The different machining times required for each part, the
machining times available on different machines and the profit on each machine
part are given in table 1. Determine the number of parts I and II to be manufactured
per week to maximize the profit.
Type of Machine Machining time required for Maximum time available
machine part (Minutes) per Week (Minutes)
I II
Lathe Machine 7 3 2000
Milling Machine 3 9 1500
Grinding Machine 1 2 400
Profit per unit ₹ 50 ₹ 100
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