.STL scan to Generataing Pattern

Hey Guys,

I have a scan, so now I want to create a custom pattern over the scan surface. The scan file is in .STL format. 

Is there is a way of converting a .STL to a workable surface in rhino? I would like the highlight the border as well, whihc is dipected by the image that I have attached. I have also attached the scan for your consideration. 

To conclude I just want to know the shortest posiible or a semi automated way of converting an .STL to a surface and then applying the pattern with highlighted boundaries.

Thank You