Can Roof Rafters Be Vaulted?
Roof rafters, unless the roof is flat, by their very nature are vaulted.
Vaulted means installed at a slope.
If your house is built with standard trusses, you can't modify the trusses easily and make a vaulted ceiling.
If your house is common framed with traditional rafters and you have a flat ceiling, you can create a vaulted ceiling with some work.
You may have to consult a structural engineer to get the guidance as to what to do so you don't collapse the roof!