I'm not an architect by far. I only build mechs, spaceships, and other vehicles. What's to stop me from building structures like those modular sets?To start, and make things as basic as possible, I went with rebuilding the set 67051 (Marvel Super Heroes Airport Battle set) into a fully covered structure. As it is, the only covered part is the front and sides, the rear's open.
While building Lego sets can be fun, especially those cool Star Wars themed sets, there are people who would go about and create their own builds out of the sets they bought, or by collecting parts from other sets and combining. They are called a ‘Moccer’, a person who build their own creation (My Own Creation or simply MOC).