How to load a .3ds file with NX?
Many 3D models in 3ds format, but NX7 does not directly open this kind of file.
Should I use a converter?
And if so, which one?
3ds format from Autodesk 3ds Max is polygonal data where as NX uses NURBS to create surfaces and solids.
The only way you could get 3ds data into NX is to convert 3ds to STL then NX can import this format but you won't be able to do much with the model as it will come in as a faceted body not a workable NURBS body, there are some basic tools in NX to clean up the model a little but the imported data would only be useful for reverse engineering.
This is a good and free polygonal converter and mesh manipulation tool http://meshlab.sourceforge.net/