Also, the engine is true 3-D in all aspects.
The SC engine was stricly 2.5-D, in other words, all calculations were done in 2-D, and then in certain cases, a modifier was applied to make it seem 3-D for gameplay purposes. So, if you setup certain parameters, you could clearly demonstrate that the engine was not doing calculations in 3-D.
I've never played SC, so I'm getting this from a person who is intimately familiar with both game and acoustic engines, who is not a member of the Subsim community, so he shall remain nameless.