Lernkartei Interaktive Computergrafik (Seite 4 von 5)

Karten	194
Sprache	Deutsch
Kategorie	Informatik
Stufe	Universität
Erstellt / Aktualisiert	24.04.2021 / 21.07.2021
Weblink	https://card2brain.ch/box/20210424_interaktive_computergrafik
Einbinden	<iframe src="https://card2brain.ch/box/20210424_interaktive_computergrafik/embed" width="780" height="150" scrolling="no" frameborder="0"></iframe>

The difference between two points is a...

vector

The sum of two vectors is a...

vector

The sum of a vector and a point is a

point

Which of the following elements describe a vector in homogenous representation?

(0 1 0)

[0 1 0 0]

(0 1 0 1)

(0 1 1)

(0 1 0)

Why do we use homogeneous coordinates?

to avoid memory padding

to reduce notation ambiguity

to uniformly represent vectors and points

to increase information density

Which of the following statements are true?

Homogeneous coordinates normally have a 0 or 1 value in the fourth component.

A frame of reference always requires orthonormal base vectors.

Homogeneous coordinate systems are bases.

Calculate the solution of the following equation

(0 2 6)

(1 3 10)

(2 4 7)

Without further information, the result (2 4 7) can be a

Vector

Point

What is the result of the following term?

1

2

3

What is a matrix?

An always quadratic array of elements arranged in rows and columns

A rectangular array of elements arranged in rows and columns.

A periodic cluster of elements arranged in rows and columns.

A square collection of elements arranged in rows and columns.

How does the transpose of the following matrix look like?

1

2

3

4

How do you add matrices?

1

2

3

4

What is the result of the following matrix-scalar multiplication?

1

2

3

4

What is the result of the following matrix-matrix multiplication?

https://lectures.hci.informatik.uni-wuerzburg.de/ss21/icg/06-02-matrix-algebra-deck.html#/recall-5

see VL

What is an identity element?

Which of the following equations involving a multiplicative identity element I are true?

AI=A^-1

A+I=A

AI=A

IAI=A

What is an inverse element?

Which of the following equations involving a multiplicative identity element I are true for all matrices A and B?

BAA^-1B^-1=I

(AA)^T=A^-1

A^-1=(IA)^T

B^-1A^-1=(AB)^-1

Given three square matrices A, B,C which of the following statements are true?

A(BC)=(CB)A

A(BC)=A(CB)

A(BC)=(AB)C

A(BC)=(AB)(AC)

Which of these matrices represent a rotation?

https://lectures.hci.informatik.uni-wuerzburg.de/ss21/icg/06-03-rigid-body-transforms-deck.html#/section-29

siehe VL

https://lectures.hci.informatik.uni-wuerzburg.de/ss21/icg/06-03-rigid-body-transforms-deck.html#/section-32

What ist the result of the following term? Explicit calculation is not required!

siehe VL

What operation does the following matrix represent?

1 0 0 -1

0 1 0 -1

0 0 1 -1

0 0 0 1

Rotating around the line of origin with the direction (-1,-1,-1)

Translation into the direction (-1,-1,-1)

Reflecting on all three planes described by the base vectors.

Which of the following matrices are NOT valid affine transformations?

https://lectures.hci.informatik.uni-wuerzburg.de/ss21/icg/06-04-affine-transforms-deck.html#/section-20

see VL

Why do we want different classes for vectors and points?

To exploit type checking and avoid illegal operations

To store both types together in data structures and collections like arrays.

To manually select correct methods by checking an object’s type during runtime.

Memory Alignment and Padding

Padding is....

used to fill-up data elemnets to achieve proper memory alignment

used to match two data elements which carry different payloads

the definition of the memory access architecture to match powers of 2

the definition of data element sizes to match the memory access architecture of the computer

used to fill-up data elements to avoid memory holes during garbage collection

Memory alignment is...

used to match tow data elements which carry different payloads

the definition of the memory access architecture to macht powers of 2

the definition of data element sizes to macht the memory access architecture of the computer

the correspondence of cache and main memory in terms of the data bus

used to fill-up data elements to avoid memory holes during garbage collection

What is to consider during the design of base classes?

Are there any common methods or properties for derived classes?

They are perfect to minimize coupling and to maximize coherence.

They should always be preferred in contrast to composition patterns

To store and access diverse derived classes in common data structures and collections

The green cube is a rotation of the red cube around the black line by pi. What steps are required to rotate the red cube onto the green one?

(line is not in centre, cube neither)

shift line to the center and the cube with it

shifting cube to the center and the line with it

align the rotation line with one axis

rotate about the aligned axis

inverse align then shift back the line and cube

What is the order, in which the single transformations are applied?

Rotation, then Scale, then Translation (T*S*R)

Scale, then Rotation, then Translation (T*R*S)

Translation, then Scale, then Rotation (R*S*T)

Translation, then Rotation, then Scale (S*R*T)

Scale, then Translation, then Rotation (R*T*S)

You know that, in general, the order of transformation matters. Under which cases is the transformation for a single object invariant to the order? The complete transformations

only contains rotation and translation

only contain similar operations. I.e. only rotations or only translations

remain the same when two consecutive transformations are swapped, e.g. (T*S*R)=(T*R*S)

....specify part-of relations and also affine transformations.

Inner nodes

edges

outer nodes

leaf nodes

... represent attributed geometry and animations.

leaf nodes

outer nodes

edges

inner nodes

Lastly, ... are vertical connections in the graph specifying parent-child relation.

Leaf nodes

edges

inner nodes

outer nodes

One of the roots (nodes without parent) of the DAG represents the ...

camera coordinate system

object coordinate system

world coordinate system

perspective coordinate system

Which coordinate system is a ray transformed to after creation?

World coordinate system

Camera coordinate system

Object coordinate system

Which of the following statements are true?

Nodes with a common ancestor always share all properties

A node with a transformation property applies this transformation to all children of this node which then is transitively applied to all child nodes.

The camera object is always outside of the graph since it specifies no geometry

After a scene graph is traversed during a general transformation traversal, all objects are represented in a common coordinate system

Why are we using matrices in a scene graph?

To define geometric objects.

To describe relative positions between objects

To describe absolute positions of objects

To describe movements.

How is a scene graph normally traversed?

breath first

shallow first

depth first

What data structure is used for iterative scene graph traversal?

a heap

a fifo

a stack

Which parts of the scene are part of the scene graph?

cameras, objects

light sources

obejct properties

coordinate system

animations

Why do we use a directed acyclic graph rather than a list as representation of the scene?

Searching objects takes less time because the scene graph is basically a tree.

Modifying a common ancestor of objects relative to a camera node affects the displayed behaviour all the descendants

Because GIT uses DAGs for branches, thus we can store object relations as files in the version control system.

The intrinsic relationships between nodes use relative rather than absolute transformations.

Assign the given tasks to the appropriate coordinate system, in which they are done best:

World Coordinates

Creation of secondary rays

Lighting calculation

Creation of primary rays

Intersection calculation

Geometry definition

Interaktive Computergrafik

Lernkarteien erstellen oder kopieren

Lernkarteien erstellen oder kopieren

Melde dich an, um alle Karten zu sehen.

SWITCHaai

Office 365

Edulog

Apple ID

Google