RTF is a global modification that replaces all towns in the game.

These are holes in the texture, not in the model.

Yes, I looked, and there were indeed holes :D

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By the way, why is the bottom of the sawmill illuminated, while the top is in shadow?

I don't know about that. It's always been like that.

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Most likely, this is how the lighting for the wood shines.

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By the way, I will slightly rework the Underground Mine and Meteor Crater visually.