So i have about 30 Buildings that i 3d modeled, they are seperated as Huge,Big,Medium and small, so all the huge onces have the same Rectanglar base width and lengh , so are the other ones, my question is how can i use my 3d models instead of genereating buildings proceduraly and how can i use those buildings base width and lengh to make city engine knows where to put the huge,big,medium and small