OBJ and FBX export quality issues from 3SM

Hi,

Having some quality issues exporting a 3Sm to FBX and OBJ.  I've created the 3Sm from points data and a high quality geotiff.

Even with the export resolution set to its maximum the quality the result is nowhere near as good as the original.

The first image is the 3SM, the following is synchro which is where I'm trying to import to.  I've added the final image which is imported into rhino.

any ideas on how to get a better output?  Thanks,