Not sure if it's been addressed before, but I've caught the obj exporter formatting numbers with commas (i.e. 1,3984.398 instead of 13984.398) which breaks any 3d software I've tried to throw the exported model at, so I'm guessing that's not intended. It's easily fixed by removing commas with a text editor, and it only affects really large models (0,7 and 8 in sootpolis central, for example).