Hi Misc - the problem is what Will mentions above - your 3DM file contains polygon mesh data and not NURBS data.

MoI is a NURBS modeler and will only load NURBS data from a 3DM file, it does not work on polygon mesh type data.

There are many different kinds of ways to represent 3D models - every program does not work in the same way or on the same kind of data.

Modo works with a system called Polygon/Sub-d modeling, where objects are made up of a large number of little facets.

MoI works with a system called NURBS modeling which is totally different from that, it uses something more like big rubber sheets rather than small facets.

It's kind of similar to the difference between working with bitmap pixel data versus vector drawing data if you are familiar with those differences in 2D drawing programs.


It is possible to export from NURBS in MoI into polygons - MoI has a conversion process that it will do when you export to a format like OBJ or LWO, where it dices up the big NURBS surface sheets into little facets to make them into polygons.

But it is not easy to go the other way and try to take little facets and glue them together into large smooth sheets. It's kind of like how you can take apples and smash them into applesauce, but if you start with applesauce it is not easy to construct apples back from that.


So the normal direction to move models between MoI and Modo is to start with a model in MoI and then export it to Modo by conversion to polygons. Since Modo does not produce NURBS data it is not generally possible to go the reverse way like you are talking about here.


There are some specialized programs that deal with reverse engineering polygon mesh data into NURBS surfaces, check out this previous thread for some links to some different programs that work in that area:
http://moi3d.com/forum/index.php?webtag=MOI&msg=2469.3

But probably your best bet is to use T-splines for Rhino (http://www.tsplines.com) which has a method in it which can convert a sub-d polygon control cage into NURBS surfaces, which can then be sent to a NURBS CAD program like MoI or Inventor.


But basically you're trying to convert between 2 very different representations of 3D data, it's not at all just a matter of saving to a different file format, the structure of the data itself is very different between polygons and NURBS.

- Michael