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
An interactive viewer for three-dimensional chemical structures.
LDraw™ editor for LEGO® style digital building instructions.
crossplatform multithreaded object-oriented render and audio engine
Realtime raytracer using SIMD on ARM, MIPS, PPC and x86
Python 3D renderer with wireless display support
3D Without Boundaries
Scanning Probe Microscopy Controller and Data Visualization Software
For building cross-platform 3D geospatial apps in Java
rayshade and POV for Mathematica Export + view
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++.