Thanks for the reply. My back ground is in Machining and Design work including 2d and 3d cad I am now using Alibre for my modeling software and now have a need to use MOI so the surfacing thing is all new to me. How I did this is I started by drawing curves with points and then used the network feature to make the surface then Boolean the surfaces together and extruded to thickness the bottom ribs were sweeps then planar and copied to the body of the part. Wrong or right I don't know I guess I am learning as I go and that's why I am asking for help. The part is just a genaric plastic cover I thought was a good place to start.