Hi Andy,
So your surface looks like Crumpled paper!!!

I opened it in 3dcoat without modifying it. Then I ran a command called "Instant Mesh" with the auto setting. I set 3200 as the poly count. If you really wanted or needed quality results, you would retopo it properly i guess.

The result below.

The retopoed mesh along side the same file imported using MoI's SubD tool:



And the Imported Mesh, alongside running Max's SubDiv9 on it.



In both cases, the imported mesh is there by means of Max's ImportObj Command.

I wouldn't try to work with the original 3dm file....