You can also just say so if you do not understand the question :D ...
The Aurora engine is the graphical engine that Kotor/Kotor2/NWN run on
Kotor uses 2 meshes to build any NPC. A body one and a seperate head one. Other games may use only one (entire person). Usually this are games where less NPC's are needed so there is no need to use body/head variety to create an artificial feel of "more different NPC's"... (examples: Unreal Tournament only has one mesh. Thus if you wanted a red suit instead of a green you needed to alter the entire Pawn... and get another one. Kotor though can just use the same head and only has to alter the body to be red. So you end with a green and red body, but the head doesn't change and can be used on both. Now they can also plant other heads on these 2 skins, while with UT you cannot)
So, now I will repeat: