I have 32bit XP which may be the cause of my problems with MeshLab. Also thanks for your info about the obj format.
You can open the obj file in a text editor
for a newbie the range of 3d formats is a bit bewildering at first.
I found a sketchUp to ASCII 3ds convertor - su2ase - which is a SketchUp plugin.
On the atari forum page is a link to an app called Biturn that converts ase files to 3ds.
3dxchange then converts the 3ds file to a vns.
I'm probably not using Biturn properly but it is making the meshes nice and small - which is exactly what I need. (I understand that small is a relative term) There are no textures coming in with this method though.
I'll need to do more research on this. I think I'll look for polygon reduction in obj or dae files. I like working with text/xml I can read.
Thanks for all of your advice.