# NPTEL Computer Graphics Assignment 3 Answers 2023

NPTEL Computer Graphics Assignment Solutions

## NPTEL Computer Graphics Week 3 Assignment Answers 2023

1. What is the basic idea behind voxels in space partitioning methods?

A) Representing objects using a collection of 2D pixels
B) Representing objects using a collection of 3D cubes with uniform size

```Answer :- B) Representing objects using a collection of 3D cubes with uniform size

The basic idea behind voxels in space partitioning methods is to represent objects in a three-dimensional space using a grid of uniform cubic elements called voxels. Each voxel represents a small portion of the 3D space and can be thought of as the 3D equivalent of a pixel in 2D images. Voxels are used in various applications, such as computer graphics, medical imaging, scientific simulations, and more, to discretize and represent the volumetric data of objects or scenes. This representation allows for efficient storage, processing, and manipulation of 3D data, making it a fundamental concept in various fields.```

2. What does BSP stand for in space partitioning methods?

A) Binary Subdivision Procedure
B) Boundary Space Partitioning
C) Binary Space Partitioning
D) Base Structure Placement

```Answer :- C) Binary Space Partitioning

BSP stands for Binary Space Partitioning. It is a technique used in computer graphics and computational geometry to recursively divide a space into two regions using planes. This process creates a hierarchical tree structure where each node represents a partitioning plane, and the leaves of the tree represent convex regions of space. BSP trees are commonly used for various purposes, such as visibility determination, collision detection, and efficient rendering in 3D environments.```

3. What does CSG stand for, and how does it represent objects in space?

A) Constructive Shape Graphics – It uses polygonal representation for objects.
B) Constructive Solid Geometry – It relies on joining spaces using Boolean operators to represent objects.
C) Composite Scene Generation – It represents objects using point clouds.
D) Comprehensive Space Grids – It divides objects using octrees for representation.

`Answer :- For Answer Click Here`

4. Which of the following operations is NOT a basic transformation in modeling transformations?

A) Translation (T)
B) Rotation (R)
C) Scaling (S)
D) Shearing (Sh)

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5. What is the mathematical representation of scaling for a point (x, y)?

A) (x+sx, y+sy)
B) (x∗sx, y∗sy)
C) (sx∗x, sy∗y)
D) (x/sx, y/sy)

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6. Modeling transformations transform objects from local/object coordinates to world coordinate system

A) True
B) False

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7. What is the general approach to apply multiple basic transformations with respect to an arbitrary fixed point?

A) Scale, Translate, Scale back
B) Translate to origin, Perform transformation, Translate back to original position
C) Rotate, Scale, Shear
D) Translate, Rotate, Scale

`Answer :- For Answer Click Here`

8. In which sequence should multiple geometric transformations be applied to get the correct result?

A) Right-to-left
B) Left-to-right

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9. What is the purpose of the composite matrix in 3D transformations?

A) To perform multiple shearing transformations on an object
B) To combine translation, rotation, and scaling transformations into a single matrix
C) To convert 3D points to 2D points

`Answer :- For Answer Click Here`

10. In space partitioning, large memory is required to store voxel-grid information

A) True
B) False

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## NPTEL Computer Graphics Week 4 Assignment Answers 2023

1. What is the process of computing the luminous intensity at a point known as?

A) Illumination
B) Lighting
C) Direct coloring
D) Indirect coloring

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2. In graphics there are typically three types of light sources: Point light source, Directional source and ______ source.

A) Spotlight
B) Ambient
C) Simple
D) Albedo

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4. Reflection from a point can occur either of two ways: Diffuse reflection and _ ___.

A) Direct reflection
B) Specular reflection
C) Indirect reflection
D) Ambient reflection

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4. _______ models work at the pixel-level, after the scene is mapped to the screen.

A) Lighting

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5. In the simple lighting model, we assume presence of a single ambient light source fully illuminating all the surfaces.

A) True
B). False

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6. Color of a surface point depends on the properties of the light source as well as the surface containing the point.

A) True
B). False

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7. In lighting model, to avoid indistinguishable overlapping of surfaces with different distances we use

A) Intensity Attenuation
B) Color Attenuation
C) Intensity Reflection
D) Color Reflection

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8. Incident light tends to reflect in all directions from a rough or grainy surface. This is called

A) Specular reflection
B) Diffuse reflection

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9. Gouraud shading limitations can be overcome with a more accurate shading model, known as the ______.

`Answer :- `
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