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.
Ficl (Forth inspired command language) is an ANS Forth interpreter written in C. Unlike traditional Forths, this interpreter is designed to be embedded into other systems as a command/macro/development prototype language. Ficl provides object extensions that can be used to wrap methods and structures of the host system without altering them.
Memchan is an extension library to the script language Tcl, as created by John Ousterhout. It provides two new channel types for in-memory channels and the appropriate commands for their creation. They are useful to transfer large amounts of data between procedures or interpreters, and additionally provide an easy interface to on-the-fly generation of code too. No need to set or append to a string, just do a simple puts.
The Snack sound extension adds commands for sound play/record and sound visualization, e.g. waveforms and spectrograms. It supports in- memory sound objects, file based audio, streaming audio, WAV, AU, AIFF, and MP3 file formats, synchronous and asynchronous playback. The visualization canvas item types update in real-time and can output postscript. New commands and file formats can be added using the Snack C-API.
Tcl provides a portable scripting environment for Unix, Windows, and Macintosh that supports string processing and pattern matching, native file system access, shell-like control over other programs, TCP/IP networking, timers, and event-driven I/O. Tcl has traditional programming constructs like variables, loops, procedures, namespaces, error handling, script packages, and dynamic loading of DLLs. Tk provides portable GUIs on UNIX, Windows, and Macintosh. A powerful widget set and the concise scripting interface to Tk make it a breeze to develop sophisticated user interfaces.
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.
trf is an extension library to the script language tcl, as created by John Ousterhout. It extends the language at the C-level with so-called "transformer"-procedures. With the help of some patches to the core the package is able to intercept all read/write operations on designated channels, thus giving it the ability to transform the buffer contents as desired. Existing transforms include Base64, UUencode, Hashes (SHA, MD5, ...), error correction codec, zlib-based compression, script level transforms.