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The model itself, in FBX format; I don't have Blender.
New here? I'm Roha — want a quick tour?
Generally speaking, I managed to solve your problems; the Tower with almost 30k polygons was exported with smoothing groups. Here's what it looks like.
The top part could be improved).

This is a model of the Magic Guild, a level 5 city Tower from Heroes 3. I planned to use it to replace the Library of Enlightenment. Making it 3x3 cells like the Arena/Marletto's Tower.
The top part is made according to canon =)
I assume that smoothing was done again using 3D Max?
I didn't do any smoothing; I just changed the object type from editable poly to another one (editable mesh).
In the simplified version of the tower, the vertices at the top are not connected, resulting in a circular hole, and some polygons are not displayed due to the unwrapping there.
Yeah, there are some flaws =)
I tried to simplify it as much as possible, and I probably didn't connect it properly in low poly.
And the texture didn't bake very well, which was partly due to the UV mapping (the cut on the back of the dome). Ideally, it would be good to clean up the patched areas in Photoshop.
But until I figure out how to maintain smooth shading during export, it's not critical. I don't like angular models; I need smooth ones =)
I don't really want to download 3ds Max (I tried it once, and Maya too, to be honest, it's not as good as Blender, but that's just my opinion).
Based on my limited experience, Maya is better suited for creating skeletons, skinning, and possibly for creating animations, while Max is more convenient for creating the models themselves (Maya has some stupid quirks that sometimes turn even simple bug fixes into a nightmare).
Let me chime in as a passerby.
Why 30k polygons for a simple tower that the player sees from a distance on the global map? The same information, without losing "quality," can be conveyed with 1k-3k polygons.

