A complete Open CASCADE Technology-based geometry kernel allowing complex 3D operations on complex shape types, with native support for concepts like brep, nurbs curves and surfaces, a wide range of geometric entities, boolean operations and fillets, and built-in support of STEP and IGES formats
A full parametric model. All FreeCAD objects are natively parametric, which means their shape can be based on properties or even depend on other objects, all changes being recalculated on demand, and recorded by the undo/redo stack. New object types can be added easily, that can even be fully programmed in Python
A modular architecture that allow plugins (modules) to add functionality to the core application. Those extensions can be as complex as whole new applications programmed in C++ or as simple as Python scripts or self-recorded macros. You have complete access from the Python built-in interpreter, macros or external scripts to almost any part of FreeCAD, being geometry creation and transformation, the 2D or 3D representation of that geometry (scenegraph) or even the FreeCAD interface
Import/export to standard formats such as STEP, IGES, OBJ, STL, DXF, SVG, STL, DAE, IFC or OFF, NASTRAN, VRML in addition to FreeCAD's native Fcstd file format. The level of compatibility between FreeCAD and a given file format can vary, since it depends on the module that implements it.
A Sketcher with constraint-solver, allowing to sketch geometry-constrained 2D shapes. The sketcher currently allows you to build several types of constrained geomerty, and use them as a base to build other objects throughout FreeCAD.
A Robot simulation module that allows to study robot movements. The robot module already has an extended graphical interface allowing GUI-only workflow.
A Drawing sheets module that permit to put 2D views of your 3D models on a sheet. This modules then produces ready-to-export SVG or PDF sheets. The module is still sparse but already features a powerful Python functionality.
A Rendering module that can export 3D objects for rendering with external renderers. Currently only supports povray, but is expected to be extended to other renderers in the future.
An Architecture module that allows BIM-like workflow, with IFC compatibility. The making of the Arch module is heavily discussed by the community here.
