Well, you're correct about bottom up. However, that's about the only hard rule.

Everything else is customizable in your slicing software, which is responsible for turning your STL into Gcode.

By default, most slicers do print the permiters, then the infill. But like I say, you can change that up. This link may help you:

http://manual.slic3r.org/simple-mode...print-settings