Hi crosetti,
I made a mistake.. I meant adding surfaces.
when I open a vectorworks 2010 file with the 2012 and try to add a new surface to an existing one, the program tells me that it can't be done because they are not on the same plane.
I guess it is because in 2012 every surface you make it's in 3d and the ones that were made in 2010 or before are not..
But still.. there should be a way.. right?