I have been thinking about it for a few weeks. It's more idea for now then a tool
I have started today and I will check how time I need it to write it.
It's a long shot but I will try.
What does the tool suppose to do?
I have a grid 5x5 with empty fields., One filed in game is 15m x 15m.
I can add with the tool what I want in my city (roads, buildings, trees) By now I have only 4 parts of the road.
I can rotate any field to match for example road's grid.
I can simply click Generate button if I'm happy from result and the tool generate lvl_def file with objects. So you will get a part of the city you like.
Then you can make your own empty room or add your txt file to existing room.
I will add more objects when tool will be ready.