Ayam is a free 3D modelling environment for the RenderMan interface.
Open Source Solid Modeling CAD
BRL-CAD is a powerful cross-platform constructive solid geometry solid modeling system that includes an interactive geometry editor, ray-tracing for rendering & geometric analyses, network distributed framebuffer support, image & signal-processing tools.
CavePaint is a small 3D-Paint program especially designed for the capabilities of a CAVE (Cave Automatic Virtual Environment) using CAVELib. Instead of common 3D-Paint programs like 3dsmax or maya, CavePaint is designed for a voxel space.
A device server inteded for (but not limited to) use with 3D input devices (like dynasight, Polhemus FASTRAK, motionstar and the magellan spacemouse). Devices can be configured via a remote TCP connection. Device data is sent to registered clients via
PyMOL is an OpenGL based molecular visualization system
PyMOL is a Python-enhanced molecular graphics tool. It excels at 3D visualization of proteins, small molecules, density, surfaces, and trajectories. It also includes molecular editing, ray tracing, and movies. Open Source PyMOL is free to everyone!
RawKee: an Open Source X3D File Format Plug-in for Alias' Maya 3D Authoring Software.
Earth orbits and coverage display in 3D on your laptop.
SaVi - simulate Iridium, Globalstar, O3b, Sirius Radio, GPS, Galileo and other satellite constellations, modify them, or design your own. Uses Tcl/Tk and Unix libraries; 3D viewing option requires Geomview running on X Window.