Viewport Clipping Planes

[L_Ruts]

I have a set of layouts that contain clipped plan views. The entire model was moved down in order to match the correct real world elevation. I would like to know what exactly I need to do to modify the clipping planes to the new elevations. I have used the VIEW command but simply modifying the elevations of the planes does not update the viewport. I have also tried using BACKZ and FRONTZ variables to no avail. The VIEWMODE system variable is also listed as "READ ONLY" when I attempt to change it within the viewport. I am trying to avoid having to cut new views, setting the proper scale and aligning the new viewport with old one.

I dont know if I need to set a variable that I'm not aware of.

[EMS_0525]

is it a 3d model? 3DCLIP? adjust the front and back clipping planes?

[L_Ruts]

Is there a way to input elevations rather than sliding the planes up and down using the display window?