What is the purpose of the assembly features in SolidWorks and can they be transfered on the parts?

Why do we use the assembly features when we can do all the features on a part level?
When I use some of the assembly features, the parts stay intact. Why?

2 Answers

The assembly features is used to machine assembled parts. In other words, machining after welding for example.

Usually machines, process lines, devices, factories is consist from many parts and these stuff must be assembled to make a final product. Imagine that is all one part. Usualy assembling may be done somewhere else and crew is interested only how to assemble this. They are not interested how part is manufactured On maintenance level , crew only wish to know what is critical part that they can order them and have it in a warehouse beacuse a overhaul time must be as short as possible in process industry.
Usualy a part is made from one material, have one finish, one price. Configuration tree is allow to you that you can same part with same dimensions but different material, different finish, different price.
When you design, you can use a parts from other manufacturer to assembly your product - you do it in assembly mode - on internet you can find almost everything. Standard parts (bolts, nuts, keyway, bearings, gearboxes, electromotores, valves, pipes, flanges, clutches,...) are often made from different manufacturers and you have'n need to drawing them only to insert in assembly - you must choose one based on yours calculation and recommendations from manufacturer. Usualy your product must have a technical documentation which prove your design and fullfill project task.