In Orthographic Camera mode, a model is displayed so all its points project along parallel lines to their positions on the screen. All same-length parallel edges display as the same length, even when you orient them so one edge is closer to you than the other. In Orthographic Camera mode, a 3D model appears flat and unlike objects observed in the real world.
Use Orthographic Camera mode to confirm visually or compare the relative dimensions of entities.
Note: The term "camera mode" indicates only the particular view method used for models in the graphics window. It is not meant to indicate that you can record actions that take place in the graphics window by choosing either Orthographic Camera mode or Perspective Camera mode.