You get multiple bodies in SolidWorks when you have simultaneous separate enclosed volumes within a part. It can be useful or problematic. Multi-body parts are not inherently good or bad, but depending on how you use them, they can mean either good news or bad news. This chapter will show you how to use them carefully to get the most benefit and avoid typical problems.
You could work with SolidWorks in such a way that you would never need to use multiple bodies inside a single part, ever. Almost everything that average users normally do can be done with a single solid body and without any knowledge of multi-body functionality whatsoever.
However, to access some more powerful functionality, and options that offer more flexibility, multi-body modeling is necessary. In fact, if you want to move on to surface modeling, multi-body knowledge is mandatory because in surface modeling, multi-body is the default.
Multi-body modeling is the gateway from basic solid modeling mainly described in the book up until now into the more advanced functionality that follows. The gateway can lead in two directions: it can lead to more power, more flexibility, more options, more advanced functionality, or it can lead to sloppy, bad habits that could get you or those who work ...