Students and faculty are free to shoot in most places, specially if it is for class purposes. But there are a few exceptions in which they have to get permission from the building administration.
Outsiders, specially for commercial shoots, need a permit, and you need to pay. Its not cheap. Some buildings need special permission on top of that. I'm not sure which office you go to, but start at the Office of the Vice Chancellor for Community Affairs. If its just you and your model, and all you are toting is just a DSLR and lens, you could take your chances in the open areas like the sunken garden, lagoon, athletic oval, etc. But anything more than that in terms of equipment or people is asking for unwanted attention from either guards, tanods, or UP security force.