In SupCom a unit can see everything in the range of its visual radius even if it was imprisoned by walls. I think that is not realistic. In some other RTS games elevations and props do affect visual field. For example, in Warcraft the units at the top of a slope will get more visual fields than the ones at the bottom, and units can't see anything hidden in forests unless trees are cut or burned.
I'm not sure if it is a design defect of this game. Has anyone tried to fix it?