I am using a 3D scanner to take a surface profile of a target that has been eroded and has a crater formed in it. I would like to be able to measure the volume of the crater to determine material loss. I have been able to import the .stl file into solidworks 2011 with no problems and have used the mesh prep wizard and created a surface, but even after creating the surface I am not able to use the surface as I was hoping. I was thinking I would be able to use a fill command or even creating a mold to get the resulting volume but so far I have not had any success. It feels like this should be a simple process, its just a crater in a flat plane. Was hoping someone smarter than I had some insight as to the best/easiest way to measure this volume from a .stl file. I have attached a sample file that shows what I'm after. Any input would be greatly appreciated.