CAD, or computer-aided design, is often used to create mechanical objects. If you’re a designer, drafter, architect, or engineer, chances are you may already be familiar with CAD. This type of software can be useful in all sorts of fields, from industrial design, mechanical design, architecture, and in fields such as aerospace engineering and astronautics. A CAD model can contain data like material properties and dimensions, as well as tolerances and manufacturing process specific information, making it a powerful tool in a designer's arsenal.
SolidWorks is considered the industry standard when it comes to CAD software, and is the software most used by professional 3D designers. It's generally thought of as much more versatile and powerful than simpler design programs such as SketchUp or AutoCAD, and much more user friendly than Creo or Inventor. For makers wishing to build skills that employers will absolutely want to see, SolidWorks is the way to go.