Select similiar direction

Is there a way to select objects with the same direction? For a 3ds max rendering it is important, that the sufaces face to the outside of the building but there are some how don’t. With dir command I can see which those are, but I wish I could select them all at once. Or give a new direction to all of them by selecting a center from which all normals face to the outside of the building?

thx in advance

You can set the displaymode to show backfaces differently this will help in selecting the faces that you want to be flipped.


I knew rhino has something like this. I just wasen’t sure how it’s name was. Thanks a lot