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.
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.
expect-lite is an quick and easy command line automation tool. Written in expect, it is designed to directly map an interactive terminal session into an automation script. expect-lite scripts use special character(s) at the beginning of each line to indicate the action. Basic expect-lite scripts can be created by simply cutting and pasting text from a terminal window into a script, and adding '>' '<' characters. No knowledge of expect is required. Expect-lite is targeted at the verification testing environment, and will produce a Pass/Fail result at the end of the script. However, its use is not limited to this environment. It includes a powerful debugger with breakpoints, step/skip, and the ability to copy/paste expect-lite lines right into a running script.
MacPorts makes the world of open source software available to your Mac. There are over 5600 software titles ("ports"), each one installable with a single command. This is probably the biggest, most up to date open source software collection for Mac OS X. MacPorts works much like the ports collections of the major BSD operating systems.
Ayam is a free 3D modelling environment for the RenderMan interface. It features good RIB export, CSG (all RenderMan primitives supported), and NURBS modelling. Features instancing, arbitrary number of modeling views, object clipboard, independent property clipboard, n-level undo, console, and Tree-View with Drag-and-Drop support.
pgintcl is a pure Tcl interface to the PostgreSQL database system. It provides an alternative to pgtcl and pgtcl-ng but does not require a compiled Tcl extension (libpgtcl) or PostgreSQL client library (libpq). This allows developers to create Tcl utilities and applications that are platform neutral. Trade-offs are slower performance and PostgreSQL protocol version dependency.