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.
Gepetto provides a framework to animate characters. It lets you record choreographies and build complex moves using elementary actions. Gepetto is fully graphical and offers real-time rendering of the animation, but there is an undelying textual language describing the moves which can be used directly.
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.
TkDVI is a DVI previewer built with the Tcl/Tk toolkit. It can use multiple windows to display multiple pages at the same time (which can come from multiple DVI files sharing a common font repository). Each window can show either a single page, two facing pages (as in a book) or sixteen reduced pages in the space of one, to check page breaks and positioning of floating items. TkDVI supports many features from xdvi, such as a magnification glass, but also adds interesting stuff like a gv-like page selector and a `rubber line' for measuring distances. TkDVI is based on a reusable Tk `image type' for DVI files which can easily be incorporated in other programs, and it is straightforward to customize and extend TkDVI itself.
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.
Wallpaper Control is a non-window manager-specific wallpaper manager for the X Window System. It aims to be a full featured utility for managing and setting your images you use as wallpaper. Features include a preview window, directory listing, and deletion of graphics from hard drive.
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.
PLplot is a library of C functions that are useful for making scientific plots from programs written in a wide variety of languages. It can be used to create standard x-y plots, semi-log plots, log-log plots, contour plots, 3D plots, shade (gray-scale and color) plots, mesh plots, bar charts, and pie charts. Multiple graphs may be placed on a single page with multiple lines in each graph. Different line styles, widths, and colors are supported. A virtually infinite number of distinct area fill patterns may be used. A variety of output devices and file formats are supported.