I've noticed a (for me) strange problem that seems randow when saving SW drawing files as DWG or DXF: Sometimes curves are not exported as smooth curves but rather asa series of loops which intersect back over each other. This doesn't happen on every file on even on every curve in the same file. Maybe one particular curve along the outline of a part will be garbled like this.
It's not evident at first, you really have to zoom way in to see it. Usually it becomes evident after attempting to use the exported file in CAM software to program a toolpath and then getting an intersecting path error.
This is NOT a CAM software error as I have checked the files in AutoCAD and in Illustrator and sure enough, if you zoom way in, the curves are not smooth but loop back over themselves.
I can try and post a pic, but maybe someones else has had this problem?