Hi Alan,

re:
> I understand that the OBJ file format may be even better than STL.

Well OBJ format supports a lot more things than STL like it can have materials in it but it is not likely that this additional information will be used by your slicer program.

Also OBJ format supports n-gons (polygons with more than 3 or 4 sides) but it's also not likely that the slicer is set up to handle those very well so you would probably want to use the option "Export: Triangles only" when you export the .obj file.

STL format is the one that is most frequently used for 3D printing data transfer.

If you want to export to a rendering program, that's when OBJ format is better to use than STL.

- Michael