Coordinates of a Viewport Are Very Large if the Viewport is in 3D Rotated View

[JC_BL]

I am trying to understand why the coordinates of the 4 corners of a viewport are ridiculously large if the viewport is viewing objects in 3D rotated view (such as viewing from South-East):

On the other hand, the same viewport viewing from Top / Front / Back / Left / Right has reasonable coordinates:

I would like to know why the coordinates of the viewport can become so large.  And I also would like to know how we can calculate the very large coordinates.

I have a related post called "How to Find the 4 Corners of a Viewport in WCS _if_ the Viewport is at an Angle?".  But I have a feeling that the title of that post may be a bit too specific.  Therefore, I need to re-phrase the question to make the question more "general".

Please help.  Thanks in advance.

Jay Chan

[JC_BL]

I hope someone can help me with this.  I am still stuck at this issue.

Please help.  Thanks.

Jay Chan

[JC_BL]

Seem like I need to set the UCS of the viewport in order to work with the coordinates conveniently.  I will see how this goes.

Jay Chan

[JC_BL · Accepted solution]

Yes, indeed I need to set up UCS instead of trying to calculate the crazily large coordinate numbers.  I use this command to setup the UCS for the viewport:

(command "ucs" "view")

This works fine.  I should have thought of that.

Jay Chan