3D Without Boundaries
A cross platform high-performance graphics system
rayshade and POV for Mathematica Export + view
For building cross-platform 3D geospatial apps in Java
Cross Platform Professional Procedural Terrain Generation & Texturing
Growth-grammar related Interactive Modelling Platform
Viewer and exporter for Unreal Engine 1-4 assets
Vivid is a modern C++ 3D engine using OpenGL4+
A shader-based software renderer written from scratch in C89
Tao3D is a programming language for real-time interactive 3D
PyMOL is an OpenGL based molecular visualization system
Highly accurate ray-tracing software system for UNIX computers
3D Software Renderer in 700 Lines
3D Charts - Templates for PovRay(TM)
Coin3D Qt GUI Library
A processing system for 3D triangular meshes
A simple and easy to use render farm for Blender
PHIGS (Programmer's Hierarchical Interactive Graphics System)