SIPP is a library for creating 3-dimensional scenes and rendering them
using a scan-line z-buffer algorithm.  A scene is built up of objects
which can be transformed with rotation, translation and scaling.  The
objects form hierarchies where each object can have arbitrarily many
subobjects and subsurfaces.  A surface is a number of connected
polygons which are rendered with either Phong, Gouraud or flat
shading.  An image can also be rendered as a line drawing of the
polygon edges without any shading at all.

sipp is available via anonymous FTP from ftp.isy.liu.se [130.236.1.3], in
directory /pub/sipp/.