Architect and engineer?

But an architect does not have the required training to determine strength of materials, beam loadings, etc.

For simple designs you don't need an engineer, but as designs become more complex, an architect provides the shape and functionality while an engineer makes sure it's safe.

im going to school for engineering....however im not sure of the answer to your question... i believe the architect would probably do all the designing and drawing up of the structure and the engineer would do all of the calculations of stresses and pipe flows and all that fun stuff....make sure the house doesnt collapse because the walls couldnt support the weight of whats above or when you flush your toilet, make sure it will actually flush out and stuff.....theres a lot involved, i could write half a book on here.

Take it from me you can have all of it done on the so called blue print BY THE ARC/ENG until one gets the inspection field experience is the best wisdom,EVEN PLANNING DON'T PICK UP ALL OF THE ISSUES