The Optical Surface Analysis Code (OSAC) is used to predict the optical performance of the Hubble Space Telescope. The analysis is described in detail and compared to previous performance prediction analyses. The mathematical foundations of the various analyses are compared and a description of the mirror data that was used as input is summarized. Finally, the analyses and their results are compared in detail. OSAC is shown to be a valuable tool for separating and analyzing the effects of misalignments, figure errors, and mid and high-frequency statistical mirror surface errors on optical performance and compares well with previous analyses.