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.
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.
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.
Tclog is a desktop Weblog application written in Tcl/Tk. Unlike most Weblog tools, it does not require server-side scripts. Instead, it uploads entries via FTP. It features RSS 1.0, HTML templates, TrackBack, Wiki-like formatting rules, indexes for the Namazu search engine, and more.
rfc2mib is a short Tcl script which may be used to extract MIB (Management Information Base), PIB (Policy Information Base), and ASN.1 modules from an RFC document. Unlike most extractors, this script is smart enough to recognize ASN.1-style comments prior to or within the module header. It also recognizes the use of the "TagDefaults" part of the module header (not used by MIB modules), module headers that are broken across multiple lines, and macro definitions.
eltclsh (editline Tcl shell) is an interactive shell for the Tcl programming language. It provides command line editing, history browsing, and variables and command completion thanks to editline features. The completion engine is programmable in a way similar to tcsh, and comes with built in completion for the entire Tcl language by default. The package also provides elwish, an interactive interpreter for the Tk toolkit. You need the editline library in order to compile eltclsh.