CAD or Computer-Aided Design is a must-have designing tool for most enterprises for designing and correcting projects. The purpose of using CAD varies from designinga small hairpin to a large township. Planning and designing using CAD is a very skillful job. Most industries use one or the other version of CAD according to their specific need.Professional CAD software is very costly due to its demand and features. A student, on the other hand, needs free CAD software for learning and designing purposes on a very small scale with fewer features. However, being a student, CAD software is very costly to buy and use. To cater to the need of such a community of first-time learners, free versions of CAD are available in the market. Many use these free versions of CAD for the purpose of practicing. See also: What Are Digital Assets? | Definition, Examples & More. As many software are available in the market, before using (or downloading), we need to know about them and select the best from the lot. After much research, I have found a few such software which is free of cost and sufficed the need of the learners. 1 Top 20 Best Free CAD Software For Windows. Here are the top 20 best free 3d cad software for Windows. Autodesk 123D Design is the free version of CAD created by Autodesk. This is the best tool for beginners to learn design, to get a solid foundation. The software is like Autodesk’s Inventor. It is very powerful yet simple to operate.