LibreCAD is a cross-platform 2D Computer-Aided-Drawing application derived from QCad, and extends it with CAM functionality. It supports DXF, LFF, CXF, and JWW files, can export to common bitmap graphics formats and SVG.
Automatic Drawing Generation is a GObject-based library that provides a non-interactive Cairo canvas specifically designed for generating technical drawings. It is intended to be used by software developers to integrate mass customization applications or to supersede parametric CAD workflows.
OpenCSG is a library that does image-based CSG rendering using OpenGL. CSG is short for "constructive solid geometry" and represents a modeling technique for composing shapes with 3D-primitives which are combined using volumetric boolean operations. Image-based CSG rendering means rendering CSG shapes without calculating their surface in object-space. Instead, the image of a CSG shape is composed directly in the frame-buffer of the graphics hardware by rather sophisticated stenciling and z-buff
KiCad is an EDA software suite for the creation of professional schematics and printed circuit boards up to 32 copper layers with additional technical layers. KiCad runs on Windows, Linux and Apple OS X and is released under the open-source GNU GPL v2 free of charge.
A full GPL'd suite and toolkit of Electronic Design Automation tools. These tools are used for electrical circuit design, schematic capture, simulation, prototyping, and production. Currently, the gEDA project offers a mature suite of free software applications for electronics design, including schematic capture, attribute management, bill of materials (BOM) generation, netlisting into over 20 netlist formats, analog and digital simulation, and printed circuit board (PCB) layout.
FreeCAD is a general purpose parametric 3D CAD modeler based on the OpenCASCADE geometry kernel. It's written in Python and its GUI utilizes Qt. It provides a modular plugin architecture and extensibility via macros and scripts, but already comes with a wide range of 2D and 3D property editing tools and transformation filters, simulation and rendering backends. Various export formats include STEP, IGES, OBJ, STL, DXF, SVG, STL, DAE, IFC or OFF, NASTRAN, VRML, DWG, and the native FCSTD files.
ZCAD is simple CAD program for technical drawings and electrical wirings and devices. It supports the DXF2000, DWG, PDF/PS/SVG/EPS and ZCP file formats and SHX or TTF fonts, is cross-platform, uses fast OpenGL rendering, allows polar tracking and taking object snapshots.