This document discusses 3D projections and clipping. It begins by describing parallel and perspective projections. It then covers various types of parallel projections like orthographic, oblique, cavalier and cabinet projections. Next it explains perspective projections and different approaches. The document also discusses window and clipping in 3D, including view volumes, finite view volumes, and 3D clipping algorithms. It provides details on clipping lines, polygons and examples. Finally it outlines the remaining tasks in the viewing pipeline after clipping.