OpenSCAD: * You write a script that calls the functions to build the geometry. (Similar to LaTeX vs. Wordprocessor) * The geometry is defined as a mesh. (Simi

OpenSCAD: * You write a script that calls the functions to build the geometry. (Similar to LaTeX vs. Wordprocessor) * The geometry is defined as a mesh. (Similar to Blender 3D for modeling.) FreeCAD: * While it can also handle meshes, the geometry it actually uses a geometric modeling kernel that knows spheres, cylinders, bent surfaces. For 3D printing you would convert it to a mesh when exporting to an STL. (This is a bit like vector vs. pixel graphics.) * While you can do everything with a script (and sometimes that's more easy) it provides a classical CAD interface where you point and click with your mouse. * There's a ton of additional functionality via plugins available such as FEM simulation, Architecture, CAM, ...