Fixing 3D scans

I did a scan with 123D catch, but it wasn’t very well done, so one side of the scan is completely missing.
right now i’m trying to fix it so it’s a solid instead of a skin so i can 3D print it.
at first i thought i could simply loft it, but loft doesn’t work on mesh.
is there a way to fill in the space between the scanned mesh and the base quickly?

(just started learning rhino)
MT.Jadefix.3dm (1.5 MB)

Hi! There are specialized tools so you do not have to use a NURBS modeler for repairing an STL mesh. I would recommend the free version of NetFabb Studio ( You have to register it to get the key though. It is very handy.