I think we need a section on this forum to discuss whether we need a 3D CAD section on this forum. 
I have not seen any prohibition or restrictions on posting 3D topics so far. Suppose those with CAD questions just continue to post in “Other topics”? If those questions become so common that an entire section is warranted, it could be added once the need has been proven. Meanwhile, the Search function still works well to research answers to previous questions.