Terrain Converter?

Is there such a thing out there? So far all I have seen are editors with the function on being able to import terrains. What I'm looking for is something to convert an already-existing map to a different terrain. Usually the process is buggy and it messes around with the doodads and terrain a bit. Is there a terrain converter out there though?

Are you talking about converting tilesets?

yes, on maps that are already finished.

In TFT, under Advanced/Modify Tileset, right there in the normal editor.