Hi Arno, Yesterday I managed to get the tool in action. The main obstacle was - as usual - the German comma as a separator. Is there anything you can do to allow operation without this being changed in the regional settings? That would be much appreciated. I could convert a big bunch of objects. Only three failed to create an MDL at all and only once I have seen the message that not all polygons can be created. On the other hand, one was an object library with 20 objects and all went trough perfectly I will now go and pack everything into a library and test how it looks in the FlightSim. I would like to send you the failed APIs mentioned above and all those where the transformation has obviously gone wrong from the look at it. I suggest that you PM me your mail address, because the forum attachment option is probably insufficient. One suggestion: an option setting would be helpful that would allow to automatically save each log under the same file name as the created mdl (with log extension).