I was just wondering how you make a surface in Cadd and be able to import it into Inventor to use as land for a site. I know when i get the surface drawing into inventor i need to add a thickness to it to have it show up. I tried a IGS and a SAT files from civil 3d cad. i dont think my surfaces are accually flat surfaces but lines connecting together to make a grid. It wont accept my drawing...am i doing something wrong? thanks everyone.