As Jim Burton says, the most recent Habware exporter or importer (I can't remember which) screws up when using scales of anything other than 1:1 (last time I looked anyway). I have reported this to Habware, who in the past have rapidly introduced modifications when I've pointed out problems, but on this occasion the view was along the lines of, well, maybe one day we'll fix it, but don't hold your breath. Far be it from me to recommend objaction Scaler, since I wrote it, and I must point out that it only works on obj files, not 3DS. As for the scale factor, the optimum depends on whether you're using metric or imperial units in Max. I think it was me that posted on the subject a year or two ago and to be honest I can't remember what the number was. However, it's largely academic as long as you use the same factor in each direction and pick a number that works reasonably with your setup.