Is there any chance the 3D Viewer will get "Perspective View Mode" back?
Follow the below mentioned steps
Go to camera tab, be make sure Orthographic mode is not cheked
If so, Check on Perspective option
Later adjust the perspective as per your requirement ...By sliding the perspective bar, as shown in the figure...
0 means full perspective........200 means orthographic
A value ranging between 30-40 on perspective slider bar will give best result.