(1) Points, and (2) Vectors.
Computer graphics consists of two activities: (1) Creating an 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 a set of points and connections between points that form the edges of a 3D solid. Here, for example is a model of 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 models.