Edit Mode is: ON• Test Canvas : 2020 Online Test 2 (NOT A REAL TEST! )21.2.CGRA151: Intro to Computer Graphics Tests, Surveys, and Pools Tests

Course Management

21.2.CGRA151: Intro toComputer Graphics

H

Course Information

Course Outline

Announcements

VStream Videos

Control Panel

Files

Course Tools

Evaluation

Grade Center

Users and Groups

Customization

Packages and Utilities

Help

This Test has 45 attempts. For information on editing questions, click More Help below.This Test has at least one attempt in progress. Deleting questions has been disabled. The attempts currently in progress are by: Hayden Riches, Georgia Barrand, Ella Wipatene, Alicia Robinson,Oliver Silk, Jessica Cooke and 11 more.

X

Test Canvas: 2020 Online Test 2 (NOT A REAL TEST! )

The Test Canvas lets you add, edit, and reorder questions, as well as review a test. More Help

You can edit, delete, or change the point values of test questions on this page. If necessary, test attempts will be regraded after you submit your changes.

Description

Instructions

Total Questions 8

Total Points 60

Number of Attempts 45

Select: Select by Type: - Question Type -

Points

Select: Select by Type: - Question Type -

Points

2020 Online Test 2 (NOT A REAL TEST)

All None

Update and Regrade Hide Question Details

1. Multiple Choice: Most graphics processing is done on

Question

Answer

Most graphics processing is done on

A. CPU

B. GPU

C. DRAM

D. Monitor

2. Multiple Choice: What is the actual 3D coordinate repr...

Question

Answer

What is the actual 3D coordinate represented by the following homogeneous coordinate:

(x, y, z, w) = (10, 15, 5, 5)

A. (2, 3, 1)

B. (4, 6, 2)

C. (10,15,5)

D. (50, 75, 25)

3. Multiple Choice: Assume that the eye (camera) is at or...

Question

Answer

Assume that the eye (camera) is at origin (0,0,0), the screen is centre at (0,0,2), the screen is parallel to xy-plane, z-axis is into screen, y-axis isup, and x-axis points to the right. Given a 3D point P = (10, 15 ,10), what are the 2D coordinates (x', y') of P after 3D to 2D perspectiveprojection onto the screen?

A. x' = 1, y' = 2

B. x' = 2, y' = 3

C. x' = 10, y' = 15

D. x' = 1, y' = 1.5

4. Multiple Choice: 3D transformations can NOT be used for

Question

Answer

3D transformations can NOT be used for

modifying a pre-de!ned primitive shape to create a new 3D model

manipulating the objects within the 3D world coordinate system.

projecting the 3D coordinates of a point to the 2D screen.

transforming the world coordinate system to the default viewing coordinate system.

5. Multiple Choice: What is the transformation represente...

Question

Answer

What is the transformation represented by the following matrix in a right-handed 3D coordinate system:

A. Rotation by 90 degrees about x-axis

B. Flip the object about x-axis

C. Rotation by 90 degrees about z-axis

D. Flip the object about z-axis

6. Multiple Choice: Assume that the eye (camera) is at or...

Question

Answer

Assume that the eye (camera) is at origin (0,0,0), the screen is centre at (0,0,2) and parallel to xy-plane, up vector is along the positive direction,the screen's width is 640, height is 480, and the x,y-coordinates on the screen are from (-320, -240) to (320, 240). Also assume that the y-axis isup, z-axis is into screen, and x-axis points to the right. The two clipping planes for z-coordinate are zf = 0.5, zb = 5. Which of the following 3Dpoints will be rejected after 3D clipping? (All the following 3D points are represented by their real 3D coordinates (x, y, z).)

A. (400, 200, 4)

B. (310, 230, 1)

C. (100, 100, 2)

D. (310, 230, 4)

7. Fill in Multiple Blanks: You are given a 3D cylinder represent...

Question

Evaluation Method Answers for: A Case Sensitivity

Exact Match y

Evaluation Method Answers for: B Case Sensitivity

Exact Match 2.5

Exact Match 5/2

Evaluation Method Answers for: C Case Sensitivity

Exact Match z

Evaluation Method Answers for: D Case Sensitivity

Exact Match x

Evaluation Method Answers for: E Case Sensitivity

Exact Match -90

Evaluation Method Answers for: F Case Sensitivity

Exact Match 2

Evaluation Method Answers for: G Case Sensitivity

Exact Match 1

Evaluation Method Answers for: H Case Sensitivity

Exact Match 1.5

Exact Match 3/2

You are given a 3D cylinder represented by the heavy strokes in the left-hand graph. This cylinder is centred at the origin(0,0,0), of which the radius is 1 unit and the height is 2 units. The axis of this cylinder is aligned along the y-axis. Please !ll inthe following blanks to describe the transformation steps needed to transform it to generate a cylinder shown in the right-hand graph. The desired centers of its two ends are (0,1,3) and (4,1,0) respectively, and the desired radius is 1 unit.

Note that the rotations you apply on the object should be the "inverse rotations" (in lecture note p203) if you are referring to theexample in our lecture notes for calculations:

The overall transformation is:

1) !rst scale the cylinder along [A]-axis by a factor of [B],

2) rotate about [C]-axis by -53.13 degrees (= -arcsin(0.8) ),

3) rotate about [D]-axis by [E] degrees. (Hint: it is also negative )

4) translate the center of the cylinder from (0,0,0) to ([F], [G], [H]).

8. Short Answer: As shown in the !gure below, you are...

Question

Answer

As shown in the !gure below, you are given a camera of which the position is e = (1,2,2) and the up vector is = (0,0,-1). The camera is

looking at l = (3, 0, 2). After viewing transform, the coordinates of the points in the 3D scene are transformed to a coordinate system where thecamera is a standard camera located at (0,0,0), with an image plane centred at c = (0, 0, 2), up vector along the positive y-axis.

Please describe 1) the transformation steps and their transformation matrices needed to convert the world coordinates to the viewingcoordinates for the given camera, and 2) show how the matrices you listed can be multiplied together to calculate the !nal combined matrixfor the viewing transform, and show the !nal single transform matrix. (All the transformation matrices need to be shown in homogeneousform)

This question will be marked by a human.

(1) The correct order for viewing transform:

1. Translate el and u to get e'l' and u' by matrix T

2. Scale e'l' and u' to get e''l'' and u'' by matrix S:

3. Rotate e''l'' to view along positive z-axis ( two rotation matrices needed: R1, R2)

-First rotate e''l'' about y-axis by 90 degrees to make it into yz-plane:

Then rotate about x-axis by -45 degrees:

4. Rotate up-vector to make it along positive y-axis (matrix: R3)

Rotation about z-axis by 90-degrees

(2) To get the single view transform matrix, we need to multiply them together as:

M = R3*R2*R1*S*T=R3*R2*R1* =R3*R2* =R3*

=

,

All None

Update and Regrade Hide Question Details

← OK

?

!!

!!

!!

!!

!!

Blackboard FAQs Library Learning Support

Question Settings

My Blackboard

Points: 4

Points: 5

Points: 5

Points: 5

Points: 5

Points: 5

Points: 16

Points: 15

Logout Fang Lue Zhang 40

Quick Links