3D reconstruction software
aka ogre v2 - scene-oriented, flexible 3D C++ engine
FlightGear Flight Simulator: free open-source multiplatform flight sim
Open Source Solid Modeling CAD
crossplatform multithreaded object-oriented render and audio engine
LDraw™ editor for LEGO® style digital building instructions.
3D Without Boundaries
Realtime raytracer using SIMD on ARM, MIPS, PPC and x86
Python 3D renderer with wireless display support
Scanning Probe Microscopy Controller and Data Visualization Software
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
Vivid is a modern C++ 3D engine using OpenGL4+
A shader-based software renderer written from scratch in C89
Vivid Engine 2 is an open source 3D Engine coded using C# and C++.
PyMOL is an OpenGL based molecular visualization system
A framework for distributed computing
3D Software Renderer in 700 Lines