This analysis is based on the stock REJECT lumps in the Ultimate Doom IWAD, and the same lumps rebuilt using RMB 3.0 with the -perfect option. A "blind spot" is defined as any bit which is 1 in the first file but 0 in the second file. Since RMB ignores all height differences between sectors, many of these can be justified as speed optimizations or as tweaks to match the "3D" topography of the level, but certain cases do produce unintentional special effects, as in E1M6.