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On the STW and MTW battle maps you don't have true 3-D models but 2-D sprites which give you the semi-successful illusion that you're playing with 3-D units. The scenery is 3-D though. Al so in RTW and MiNO the furthest zoom level uses sprites, automatically generated from the 3-D models (which concerns modders/modellers), instead of the models themselves.

I'm sure others could word it better but hth anyway.
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