How to save your assembly as a part file showing external surfaces only. As products get more complex and assemblies more detailed, our models can start taking more computing power than our computer has, slowing us down. Saving some subassemblies as parts showing just the external faces can save you time as you work on your assembly. It can also be used to share your models with other companies without showing the internal mechanisms that make your designs work. There are many other tools that are there to make your life easier as you work on your assemblies, check them out!