Only certain textures apply negative cover - I believe these are found in the texture folders with "road" in their name (nm_road_dirt, nm_road_trim, stone_road, road_asphalt).
Also not sure what you mean by grass removed where they built the tier. I think you mean there is a dirt splat underneath the buildings they're building - I can't imagine any way around that.
thank you sir. yeah i see the dirt splat happens on official maps.
also, i changed my map name from "2nd try" to "pionersky" but it keep saying '2nd try' on it... i saved with the new name and changed the name on scenario tab. help please...