(1) Points, and (2) Vectors.
Computer graphics consists of two activities: (1) Creating a three dimensional imaginary world inside a computer, and (2) producing two dimensional images of that world from various viewpoints. A graphics program is like a tourist wandering through a fantastic landscape taking pictures with a camera. With computer animation, the virtual tourist is equipped with a movie camera.
The imaginary landscape is built of objects in three dimensional space. Each object is defined by the points and lines that lie on its surface. Above, for example, is a winter landscape (done by Tuan Phan).
The model consists of points and the line segments that connect them. To make a realistic picture, more work is needed to fill in the area between line segments and to apply lighting.
Can a sphere be modeled with points and lines?