I got frustrated because I couldn't find any converters for rigs of rods meshes, so I made my own! Just download the zip on this github link and follow the instructions. Download a preliminary converter to turn your.mesh files into .mesh.xml files. I used this one Extract the zip and open the html file using your browser. - make sure to extract as this will not work otherwise Upload the mesh.xml, name your file and download it. It will be an stl which you can import with blender or most other modelling tools. Use this tool to convert old meshes for beamng or anything you'd like. Here's the Gavril MZ2 from Rigs of Rods converted:
I chose it because it was easy to convert to. Also, those mesh.xml plugins are only for exporting. I needed an importer. The only other that you will find hasn't been updated since around 2005-2006
There is an importer for xml, but it works only with Blender 2.49b. Probably can be updated for the latests versions. http://www.ogre3d.org/tikiwiki/BlenderImport
This is the one I was referring to. Since I can't do python, I decided to do this because I found it easier. It also didn't work for me even with the correct version of blender and python.
Some importers may check if STL is a fully airtight mesh, for a start. STL only supports 1 mesh, 1 material, no UV data. It's a fairly simple format mainly used for 3d printing.
