exporting to .3ds changes the scale I have a .3ds file someone gave me that will load in fine. I will edit it a little bit, just translating so i can change the point of origin, I export as .3ds again. If I reload it, it will be far smaller.

Is there a setting somewhere that decides what scale to maintain when it exports an object?
I haven't tested this, but the 3ds import has an option for size constraint that controls the model scale while importing, setting it to zero should stop the scaling from happening.