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!
The Pure Data (short Pd) project on SourceForge unifies the extensions (or externals) written for the Pure Data Graphical Computer Music System written by Miller Puckette with contributions from many others.
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.
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.
Ayam is a free 3D modelling environment for the RenderMan interface.
gMax graphic tools for jMax
A Tcl/Tk widget for OpenGL rendering.
Togl provides a platform independent Tk widget for using OpenGL rendering contexts.
3D Motor Sports Simulator
It is an extension of Wish to Tcl/tk and includes a new widget called glview. Each glview widget can draw a 3D view and does OpenGL work in Tcl/Tk, a high-level language, if Tcl is Operating System independent then we can build OpenGL applications independent of the operating system.