CSG-based - models are built via combinations of basic shapes like spheres and cones, rather than extruded from arbitrary sketches.Focused on analysis, rather than modelling (specifically ballistics research).BRL-CAD is a powerful cross-platform open source solid modeling system that includes interactive geometry editing, high-performance ray-tracing for rendering and geometric analysis, image and signal-processing tools, a system performance analysis benchmark suite, libraries for robust geometric representation, with more than 20 years of active development.Focused on numerical simulation, but can apparently also edit CAD data.

Import from OBJ STL SVG SVZ export to POV OBJ STL.

Here is an example of FreeCAD v0.15 with Assembly2 module in 2015: Here is an example of FreeCAD v14 in 2015:

Import/export to standard formats such as STEP, IGES, OBJ, DXF, SVG, U3D or STL.

Built-in python interpreter for macros and scripts.Those extensions can be as complex as whole new applications or as simple as python scripts or self-recorded macros.' 'A modular architecture that allow plugins (modules) to add functionality to the core application.Supports brep, nurbs, booleans operations or fillets.

Based on OpenCasCade and Coin3D (an implementation of Open Inventor).

Feature-based, parametric, with 2D sketch input with constraint solver.

Focused on mechanical engineering and product design.

2013) added assembly module is a decisive step forward allowing productive work.

The most promising open source 3D-CAD software by far, but still has some way to go.

No native CAD functionality so it is directly suited to CAD use, though there are: BlenderCAD, and - though it can be used for very basic prototyping, and is useful for rendering and animation.

Focused on artistic 3D modelling and animation.

Tracking of designs by modules, lifecycle product management. Because the open-source options for CAD are rather limited (there are currently no good open source parametric 3D CAD programs), significant closed-source programs are also listed at the end. Here are some open source options for CAD.

3.1 PTC Creo Elements Direct Modelling Express 4.0.

Are there any simple cad programs