Chapter 10: Computer Graphics

Question 1

2D and 3D graphics

Answer 1

• 2D graphics: deals with manipulating 2D images

- 3D graphics: deals with producing and displaying images of three dimensional virtual scenes.

Question 2

• The process of creating 3D-graphics consists of two main steps:

Answer 2

• modeling (The process of representing a real-world object or phenomenon as a set of mathematical equations)
  
  • rendering (The process of generating a photorealistic or non-photo-realistic images from a 2D or 3D model by means of a computer program)

Question 3

Modeling objects

• Shapes are represented by polygonal meshes, obtained from:

Answer 3

• Shapes are represented by polygonal meshes, obtained from:
  Mathematical equations
  Bezier curves and surfaces
  Procedural models

Question 4

Reflecting and refraction

• Reflection: l
• Refraction:

Answer 4

• Reflection: light rays bounce off surface:
  Specular light
  Diffuse light
  Ambient light
• Refraction: light rays penetrate surface

Question 5

Rendering

Answer 5

• Clipping: Restricts attention to objects within view volume
• Scan conversion or rasterization: associates pixel positions with points in scene
• Shading: determines appearance of points associated with pixels

Question 6

Local and global lighting models

Answer 6

• Local lighting model: Does not account for light interactions between objects
• Global lighting model: accounts for light interactions between objects, for example using ray tracing.

Question 7

Ray tracing

Answer 7

• Ray tracing is a rendering technique for generating an image by tracing the path of light as pixels in an image plane and simulating effects of its encounters with virtual objects.

Question 8

Animation

Answer 8

• Storyboard: sequence of sketches summarizing the entire animation
• Frame: one of many images to create animation
• Key frames: frames capturing the scene at specific points in time
• In-betweening: producing frames to fill the gap between key frames

Question 9

Simulating motion

Answer 9

• Dynamics: applies laws of physics to determine positions of objects
• Kinematics: applies characteristics of joints and appendages to determine positions of objects:

avars and motion capture