Computer-aided design (CAD) is the use of computer systems to assist in the creation, modification, analysis, or optimization of a design.
SketchUp Free is the simplest free 3D modeling software on the web — no strings attached. Bring your 3D design online, and have your SketchUp projects with you wherever you go. You don’t need thousands of bells and whistles to draw in 3D... All you need is your idea, and room to draw.
FreeCAD is a truly open source project and if you would like to help fix bugs, implement new cool features or work on the documentation, we invite you to join us and create a software that benefits the whole community.
While the FreeCAD core functionality is coded in C++ for robustness and performance, large parts of the external layers, workbenches and and almost all the communication between the core and the user interface is coded in Python, a flexible, user-friendly, easy to learn programming language. From Python code, you are able to do just anything in FreeCAD, from simple one-line commands in the integrated Python console to recording macros, coding your own tools up to full custom workbenches.