Orthographic camera mirrored in viewport?

Question

I'm trying to render a building using an orthographic camera. The first side of the building works fine, but when I mirror the camera to the other side of the building the camera is in the right position but the view through the camera is mirrored on the Y axis.

I tried different things:

1. Mirror the camera again and rotate it around 180°. Doesn't work, the viewport is still mirrored on one axis.

2. Apply Rotation, Location and Scale (doesn't work either)

My question is, how do I fix this behavior?

PS: I fixed it with new camera - but the question, or the answer is still interesting.

Answer 1

This is because the Object mode Mirror tool works by scaling -1. (the same thing will happen if you manually scale the camera by -1.) You will also notice that in addition to the viewport being mirrored, Object Normals appear reversed.

from the wiki about Edit mode mirror:

The mirror tool in Edit mode is similar to Mirroring in Object mode. It is exactly equivalent to scaling by -1 vertices, edges or faces around one chosen pivot point and in the direction of one chosen axis, only it is faster/handier.

note that using an Orthographic or Perspective camera does not change this behavior. It is the same on both.

(as already mentioned by Polosson),
The solution is to Rotate the camera instead of mirroring it.

Also as already mentioned by Polosson, one way to do this would be to

1. Select the building, and press Shift+S > Cursor to selection
2. Press . to change the Pivot point to Cursor
3. Select the Camera and rotate around the Z axis by 180 degrees. (R+Z+180)