converting multifaced surface file to solid body

I have a step file that I received from a client who did 3d scanning a multi surface part, after opening in Solidworks the file has more than 5000 faces and edge, I tried every method I know to convert this file into a solid body but nothing worked, does anyone has any experience in converting these type of files? please see attached image on how the part looks, due to client NDA, I cant share the files or anything, hope you guys understand.