The reason for this blog article is to save you from the terrible time I had exporting a polygon mesh into a solid. Basically taking a mesh file and turning into a .iges or similar for 3d printing. After searching the forums and testing out tools that claim to do the job with no luck I had to get busy...
It is possible to take a mesh into Rhino and use the MeshToNumb command, but the mesh needs to be under 20,000 poly and once it is converted it is not smooth and for 3d printing you probably want it smooth. In 3ds Max there is a way to turn your model to Nurbs and export as an .iges. For small models this may work but not for me. If you right click on the model and Convert to Patch and once that is done right click again and Convert to Nurbs. I have not successfully used this method because I have never had the time to wait for the conversion so be warned it does take sometime.
So in 3ds Max there is an export to .iges file in the export box. File>export but unless your model is in Nurbs rather than ploys then this option won't work. So here is how I managed to get quite a heavy max scene into a solid format. This is in no way the correct method but if there is one I would love to know about it.
So here we go with my method. In 3ds Max select your mesh and go to File>Export as .obj. Then open this great tool called 3d Exploration which can be downloaded here. Navigate to the .obj file in here and save it out as a .stl file.
Open up Rhino and import the .stl file. Select the mesh and type in the command bar MeshToNurb. Once this is done select the mesh and delete it, then you should be left with the nurb object. Now all you have to do is export it as an it as an .iges :)