Slam is a mature IC Layout editor with the ability to edit very large designs (such as stream files larger than 10GB). Novel features include threading for redraw, support for displaying on multiple X servers simultaneously, and a Tcl interface to the database for user extensibility. The system is a library based system with multi-user support. Programmable structures (P-Cells) are available in Tcl. The editor includes gds input and output.
GraphicsMagick is a robust collection of tools and libraries which support reading, writing, and manipulating an image in over 90 major formats including popular formats like DPX, DICOM, BMP, GIF, JPEG, JPEG-2000, PDF, PNG, PNM, SVG, and TIFF. A high-quality 2D renderer is included, which provides a subset of SVG capabilities. C, C++, Perl, Tcl, and Ruby are supported. Originally based on ImageMagick, GraphicsMagick focuses on performance, minimizing bugs, and providing stable APIs and ABIs. It runs on all modern variants of Unix, Windows, and Mac OS X.
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.
SaVi is satellite visualization software that lets you create, run, examine, and modify satellite orbits in two and three dimensions. Simulations of Iridium, Globalstar, Galileo, GPS, and other satellite constellations are included. SaVi requires Tcl and Tk on a system with Unix libraries. SaVi works well with the 3D renderer Geomview. Geomview is optional, though recommended for its 3D rendering capabilities.
The Model Railroad System is a software package that can help you run your railroad. It allows you to operate your layout, from running trains to working your signals and switches. It has support for a network of Bruce Chubb CMR/I USIC, SUSIC, and/or SMINI nodes, and/or a network of Lenz's XPressNet DCC nodes. Azatrax USB-connected Model Railroad Detectors are supported. Software to create switch lists for freight car forwarding and create timetables for your railroad are included. There is software to help with photographing your trains, and to compute the correct value for those pesky dropping resistors for LEDs and/or incandescent lamps.
Remind is a full-featured calendar/reminder program featuring sophisticated date calculation, moon phases, sunrise/sunset, Hebrew calendar, alarms, PostScript output, an X front-end, multilingual messages, and proper handling of holidays. It also includes scripts for making a nice WWW calendar server.
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.