Class 12: How 3D Computer Graphics Work

For this assignment, I watched an overview video highlighting some of the key points and basics of how 3D computer graphics work. The video was very informative, and broke things down into 3 basic parts; vertex points/vertices, polygons and lighting/normals. I had no idea what any of these things were used for in 3D graphics prior to this tutorial video, but since watching I now have a basic understanding of how these things work and what they are used for. Here is an overview of what I learned, along with some screenshots from the video to help explain which part I am referring to.

The video started out by explaining what vertex points are, which are basically unconnected dots on a screen that will eventually be connected to form a triangle or polygon. This is what is known as 3D Geometry, and is very important because anything we see in a videogame or computer animation uses 3D geometry to make up these points, which are then connected to form the shape of whatever it is we are seeing in the game/animation.

Next, the video moved on to polygons and texture mapping. As we can see in the picture, the outline of the video game character that is pictured is actually composed of many small triangle/polygon shapes that are made by connecting the dots seen before in the part about 3D geometry. This conjunction of polygons is known as a polygonal mesh, and it is then texture mapped, in this case with some barbarian type skin/armor to appear as what the game designers want it to look like when people play the game.

The last thing talked about was lighting and normals. Lighting is pretty straight forward, from the picture we can see a small light was introduced in front of the video game character, and thus causes the front of the character to be lit up and more visible than the back half of the character. Normals come in to play in making this kind of thing happen; how it is done is by using a vector, which is more or less a line/arrow that points out of each small polygonal plane that constructs the full video game character. The more directly this line is pointing toward the light source that is introduced, the brighter that part of the character will appear. So for this example, the front of the character has vectors that are pointing toward the light, which allows us to see the characters armor and face, and the vectors on the back of the character are pointing away from the light, causing them to appear much darker, giving it a shaded look.