What's the difference between i3DP, IBF, and STL format files?

STL file is the file resulting from your CAD software design and used by ALPHA AI.
i3DP is the file that contains the design parameters including orientation and supports. 

IBF is the file sent to the printer that contains the printing instructions.
ALPHA AI can also export an i3DP file into STL to be used by other slicing software.