Why the displayed model was cut off after using Orthographic Camera?

Jul 24, 2014 at 1:45 AM
Edited Jul 24, 2014 at 1:46 AM
I created a large cylinder 2000 diameter and 1000 height. The inside diameter is 1988. It was displayed all in Perspective Camera. After I change the camera to Orthographic, it was cut off.

Anyone could help me to adjust the Orthographic Camera setting to display a model larger than 2000?

Thanks in advance.