Vargas, if the building your wanting to model is masonry, measuring the exterior - including the grade line - is easy, count the bricks.

I, too, had tried several different CAD programs over the years, as well as some more basic drawing programs to draw up designs for furniture for my woodworking hobby. They were all either too basic or way too involved to learn as quickly as I wanted to get going. Heard about Google SketchUp on a woodworking forum, downloaded it, did the initial tutorials and some other stuff online and never looked back. An excellent tool at just the right level for getting results quickly, and for continueing to learn and explore.