Berkeley DB (libdb) is a programmatic toolkit that provides embedded database support for both traditional and client/server applications. It includes b+tree, queue, extended linear hashing, fixed, and variable-length record access methods, transactions, locking, logging, shared memory caching, database recovery, and replication for highly available systems. DB supports C, C++, C#, Java, PHP, and Perl APIs. It supports key-value pair (NoSQL), SQL, and Java Object formatted data. It is available for a wide variety of Unix platforms as well as QNX, Android, Mac OS X, and several varieties of Windows.
BRL-CAD is a powerful constructive solid geometry solid modeling system that includes an interactive geometry editor, ray-tracing support for rendering and geometric analysis, path-tracing for realistic image synthesis, network distributed framebuffer support, and image and signal-processing tools.
e4Graph is a C++ library that allows programs to store graph-like data persistently and to access and manipulate that data efficiently. With e4Graph, you can arrange your data in the most natural form that reflects the relationships between its parts, rather than having to force it into a table-like format. The e4Graph library also allows you to concentrate on the relationships you want to represent, and not on how to store them in a database. You can modify data items, and add and remove connections and relationships between pieces of data on the fly. e4Graph allows you to represent an unlimited number of different connections between pieces of data, and your program can selectively manipulate the data according to the relationships it cares about, not having to know about other connections represented in the data set.
f/Calc is a utility to calculate lens formulae for photographers so you can focus on the artistic bits rather than on the mathematics behind it all. f/Calc can do "f" number arithmetic, and can calculate depth of field, hyperfocal distance, the field of view of a lens, the angle of view of a lens, magnification, and how the focal length of the lens on the camera changes the way the spot metering function works. In addition to the Unix/Linux Tcl/Tk version, there are native Windows, Palm OS, and Macintosh versions as well.
OMNeT++ is a C++-based object-oriented Discrete Event Simulation framework, primarily targeted at the simulation of communication networks and other parallel/distributed systems. It includes a graphical network editor, a network topology description language, a rich simulation class library, multiple execution environments (both GUI and command line), a result plotting tool, detailed documentation, many sample simulations, and much more.
The Nebula Device is a free multiplatform game engine currently running under Linux and Windows. It uses OpenGL and/or Direct3D for rendering and Tcl/Tk for scripting. Living C++ objects can be browsed and manipulated at runtime from the builtin console, or remotedly from a minimal terminal based console app. A powerful channel animation system allows any floating point attribute to be animated, and specialized animator classes allow things like realtime bone animation with weighted vertex skin.
VMD (Visual Molecular Dynamics) is designed for the visualization and analysis of biological systems such as proteins, nucleic acids, lipid bilayer assemblies, etc. It may be used to view more general molecules, as VMD can read standard Protein Data Bank (PDB) files and display the contained structure. VMD provides a wide variety of methods for rendering and coloring a molecule: simple points and lines, CPK spheres and cylinders, licorice bonds, backbone tubes and ribbons, cartoon drawings, and others. VMD can be used to animate and analyze the trajectory of a molecular dynamics (MD) simulation. In particular, VMD can act as a graphical front end for an external MD program by displaying and animating a molecule undergoing simulation on a remote computer. VMD uses OpenGL and OpenGL Programmable Shading Language for high performance rendering of large structures.
World Foundry is a 3D level game engine and asset production pathway with over 170,000 lines of code. It was originaly created as a commercial product, but is now being released under the GPL. The engine was designed from the beginning to be cross platform, and ran on Windows (DirectX, GL), and the Sony Playstation. The production pathway ran on Windows, and extended 3DStudio Max to be our level editor. The engine is currently being ported to Linux (it runs, but needs work), with plans to port the production pathway as well. Developers are wanted to help with this effort.