Hello Peteroznewman,

i have followed as per your comment Filling the rectangular hole in the ground is easily done with this tool.    this is working fine for now. however will you please give a brief idea how to extrude the buildings separately. i believe i am getting all the single faces of each building and there are numerous such faces, aslo i am not able to extrude each face properly. will you please show a quick tutorial or images showing how to extrude the buildings. since we are new, we need some assistance.