CS426 Lecture 6 Flashcards

Flashcards based on the notes from CS426 Lecture 6, covering topics like arc ball cameras, 3D models, platonic solids, and visibility problems in computer graphics.

What is the typical viewing time an average visitor spends in front of a work of art, according to a New York Times article?

15 to 30 seconds

What is a Tesseract also known as?

Hypercube

What is the Schläfli symbol for a Tesseract?

{5,3}

What is the Schläfli symbol for the 3D 'Shadow of a Tesseract'?

{4,3,3}

What are the five platonic solids?

Tetrahedron, Octahedron, Icosahedron, Cube (hexahedron), Dodecahedron

What is the golden ratio?

Approximately 1.618

What are the three camera types?

1st person, 2nd person, 3rd person

What coordinate system is used for the Arc Ball camera?

Spherical Coordinates

In the Arc Ball camera implementation, what do phi and theta represent?

Latitude and Longitude, respectively

What does FOV stand for, in the context of projection?

Field of View

What is the purpose of culling in 3D graphics?

To decide which polygons should be visible when mapping from 3D to 2D

What is the Painter's algorithm?

Sorting objects by Z value, drawing most distant objects first, finishing with the closest

What is Frustum culling?

The process of removing objects outside of the view frustum from the rendering pipeline.

Define Vertex in 3D Graphics

Usually a corner of a polygon or polyhedron.

Define Edge in 3D Graphics

A line segment where two faces or surfaces of a polyhedron meet.

Define Face (Polygon) in 3D Graphics

Flat/planar. A face of a polyhedron is any of the polygons that make up its boundaries

What is stored in the graphics card's RGB buffer?

Image in the form of a 2D array containing the red, green and blue values for each pixel location

What information does the Z buffer record?

Distance from the camera to the nearest object in the scene for each pixel location

What is the purpose of the alpha buffer?

Records information about how to mix each pixel in the RGB buffer with new pixels being drawn into the buffer

What is a pixel?

The smallest addressable component of an image.

What is Z-culling?

The method used by the graphics card to make sure the pixels produced by objects nearest the camera are the pixels that remain rendered in the final image.

What is Occlusion culling?

An algorithm to reduce the number of objects in the scene that would not be visible in the final scene from being rendered and then subsequently z-culled.

Why should Znear and Zfar never be set to extreme values?

Can cause primitives at slightly different ranges to be rendered in the wrong order leading to artifacts.