I searched OpenGL on this forum, and found this:
I solved my problem.
After some changes in the settings related to 3D modeling, in the window: Options> Work Environment> Advanced Options Redraw, I disabled the option "Open GL 3D Antialiasing". 3D modeling with Open GL engine has once again worked.
Thanks to the staff and to partecipaneti the Forum.
thanks
It worked for me. Sorry for the dust-up. Kind of a AC-Talk newbie.