Hi Andy, yes that method will generate lines, not faces. I guess Alibre does not try to load curves from .3dm files.
CAD programs are not designed to operate on models diced up into tens of thousands of little triangles. CAD programs expect larger smooth surfaces.
So it's difficult to do what you're trying to do. The type of data you have obtained from the scanning is meant to be loaded into a polygon mesh editing program, not a CAD program.
The way to do what you want to do is import the original mesh file (50,000) into a poly-modeller (blender)
Build a new model around the original all in quads and go as low poly as you can and keep the shape (using the subdiv modifier to help)
then you can import the new lowpoly model into Moi using the subdiv import.
I don't know if -what I want to suggest- will be helpful for you or not!
>when I try to import it into MoI3D V4 it takes a very long time on my fast PC.
I also once tried to import an Stl in MOI so, I opened Blender and saved the Stl file as an Obj but it took a lot of time to be imported in MOI and it never imported it!
Then I realized there were overlapping points (vertices). so, in Blender I did
something used to be called (removing doubles!) and then saved the file as an Obj. This time I was able to import it in MOI without any issue!
I don't know if you checked your model for double vertices or not but I recommend you to check that before importing it in MOI.
I was able to import your attached model in MOI as an Obj but only after I removed over 4000 excessive vertices using Blender.
Hope this method will help you.