SketchUp, now managed by Trimble Buildings, is a free 3D CAD Program. It may not be the most beautiful CAD software out there, but it has the tools most people will need. You can design houses, furniture, cars, and much more. If you are unaware what a CAD program is, it’s software to design structures, various parts such as for cars, electronics, etc, and nearly everything that needs to be designed. CAD software comes in both 2D and 3D versions, and also a “4D” version which includes time, so you can animate your design.
Other than the use of CAD for designing products, it’s also used for Video Games, movies, and other media. This software can create the models used in games, such as the players, weapons, environment. The CGI or “Special Effects” in movies are partially designed in CAD software as well.
SketchUp also has a Pro version that provides extra features, such as turning your 3D Drawing into a print view, and includes a lot of other features for designers. But without the Pro version, you can still get a lot of use out of SketchUp. I have the free version, and have designed many things using it.
If you want SketchUp, you can download it on their website at SketchUp.com