How many 2D pictures can be produced from one 3D model?

Infinitely many.

Applet |
Snapshot of Applet in case you don't have Java |

For example, the applet on the left projects a 3D model of a box onto the 2D view. Different positions of the viewpoint (use the slider) produce different 2D images. The 3D vectors of the model are being projected onto the viewing surface to form the 2D vectors of the image.

Are two vectors and a point enough to define a plane?