(SEM VII) THEORY EXAMINATION 2023-24 COMPUTER GRAPHICS AND PRODUCT MODELING

KME075 – COMPUTER GRAPHICS AND PRODUCT MODELING

B.Tech (SEM VII) – Theory Examination
Time: 3 Hours | Max Marks: 100

SECTION A

(Attempt all questions in brief – 2 marks each)

a. Characteristics of B-Spline curve

B-Spline curves provide local control, smoothness, flexibility, and continuity. They are defined by control points and basis functions, do not necessarily pass through control points, and are widely used in CAD due to stability and smooth shape control.

b. Difference between C₀ and C₁ continuity

C₀ continuity: Curves meet but may have a sharp corner (position continuity).

C₁ continuity: Curves meet smoothly with the same tangent direction (slope continuity).

c. Geometric transformations

Geometric transformations modify object position, size, and orientation using translation, rotation, scaling, reflection, and shearing. They are represented using transformation matrices in computer graphics.

d. Illumination and shading

Illumination models calculate light interaction with surfaces, while shading determines how colors and intensities are applied to pixels. Common shading models include flat, Gouraud, and Phong shading.

e. Rendering

Rendering is the process of converting a 3D scene into a 2D image by applying lighting, shading, texture, and visibility algorithms.

f. Anti-aliasing

Anti-aliasing is a technique used to reduce jagged edges (aliasing) in images by smoothing object boundaries using color blending or sampling techniques.

g. Importance of product strategy

Product strategy defines product goals, target market, value proposition, and lifecycle planning. It ensures competitiveness, customer satisfaction, and long-term business success.

h. Concurrent development of product and process

Concurrent development means designing the product and its manufacturing process simultaneously. It reduces development time, cost, and improves product quality.

i. Need of organization process management

Organization process management ensures standardization, efficiency, quality control, continuous improvement, and alignment of processes with business objectives.

j. Factors promoting innovation and continuous improvement

Key factors include leadership support, employee involvement, training, R&D investment, customer feedback, and a culture that encourages creativity and learning.

SECTION B

(Attempt any three – answers provided for ALL)

2(a). 8-way symmetry of a circle

The 8-way symmetry method draws a circle by calculating points in one octant and reflecting them across axes and diagonals. This reduces computation and improves efficiency in raster graphics.

Steps:

Compute points in first octant                          Reflect points into remaining seven octants

(Diagram to be drawn in exam)

2(b). Need for concatenation of transformations

Concatenation combines multiple transformations into a single matrix, improving efficiency.

Care required:

Order of transformations is important               Matrix multiplication is not commutative

Homogeneous coordinates should be used

2(c). IGES file structure

IGES (Initial Graphics Exchange Specification) is a neutral CAD file format.

Structure includes:                                           Start section

Global section                                                    Directory Entry section

Parameter Data section                                      Terminate section

It enables data exchange between different CAD systems.

2(d). Developing Services and Product Service Systems

Product Service Systems (PSS) integrate products and services to deliver value.

Process includes:                                               Market analysis

Concept development                                         Service design

Integration with product                                      Lifecycle management

PSS improves customer satisfaction and sustainability.

2(e). Intellectual Property Issues in Product Development

IP issues include patents, copyrights, trademarks, and trade secrets. Protecting IP ensures innovation security, legal ownership, competitive advantage, and prevents unauthorized use.

SECTION C

3(a). Bresenham’s Line Algorithm

Given line from (5,5) to (13,9):                                     Slope = (9−5)/(13−5) = 4/8 = 0.5 (<1)

Using Bresenham’s algorithm:                                     Initial decision parameter

p0=2Δy−Δx=2(4)−8=0p_0 = 2Δy − Δx = 2(4) − 8 = 0p0​=2Δy−Δx=2(4)−8=0

Plot successive points by updating decision parameter.

Rasterized points:                                                      (5,5), (6,5), (7,6), (8,6), (9,7), (10,7), (11,8), (12,8), (13,9)

3(b). Bezier vs Cubic Spline Curves

4(a). Rotation of triangle by 45°                 Given A(0,0), B(1,1), C(5,2)

Rotation matrix:

[cos⁡45−sin⁡45sin⁡45cos⁡45]\begin{bmatrix} \cos45 & -\sin45 \\ \sin45 & \cos45 \end{bmatrix}[cos45sin45​−sin45cos45​]

After rotation:                                                A′ = (0,0)

B′ ≈ (0, 1.41)                                                   C′ ≈ (2.12, 4.95)

4(b). 3-D transformations                          Scaling: Changes size

Rotation: Changes orientation                    Translation: Changes position

Reflection: Mirror image                             Used extensively in animation and modeling.

5(a). Polygon clipping

Polygon clipping removes portions outside the clipping window.

Advantages over line clipping:                   Handles complex shapes

Preserves polygon integrity                            Reduces rendering load

Algorithms: Sutherland–Hodgman.

5(b). Visible face detection methods

Methods include:                                          Back-face culling

Z-buffer algorithm                                        Painter’s algorithm

Scan-line method

They remove hidden surfaces to improve rendering realism.

6(a). Factors for good product design & physical realizability

Factors include functionality, ergonomics, aesthetics, manufacturability, cost, safety, and sustainability.

Physical realizability:
Ensures the product can be practically manufactured using available materials and processes.

6(b). Financial feasibility vs economic worth

Financial feasibility: Focuses on cost, profit, ROI.

Economic worth: Considers long-term value, social and environmental impact.

7(a). Qualifications and opportunities for product design engineer

Qualifications:

Engineering degree                                           CAD/CAE skills

Creativity and problem-solving

Opportunities:

Automotive industry                                          Consumer products

Aerospace                                                          Industrial design firms

7(b). Preliminary studies & value of appearance

Preliminary studies:                                         Market research

User needs                                                          Material study

Cost analysis

Value of appearance:                                        Aesthetic appeal that influences customer perception.

Types of value:

Functional value                                                 Aesthetic value

Economic value                                                  Social value