DXF group code 10 and 11

I am having trouble with trying to find the start and end points of a line in lisp and acad 2005.

When in ucs world, the start and end points match dxf group 10 and 11. However, as soon as I change to an isometric view and rotate ucs (say 90 deg about world x) it seems to swap the y and z axis values???

This is the DXF groups and list information of one line:


Command: (setq a (entget (entlast)))
((-1 . <Entity name: 7ef742b8>) (0 . "LINE") (330 . <Entity name: 7ef58cf8>) (5
"147") (100 . "AcDbEntity") (67 . 0) (410 . "Model") (8 . "0") (100 .
"AcDbLine") (10 -31319.5 -11220.7 2.22045e-012) (11 -31319.5 -11220.7 13619.1)
(210 0.0 -1.0 2.22045e-016))
Command: list
Select objects: (entlast)
<Entity name: 7ef742b8>
1 found

Select objects:

LINE Layer: "0"
Space: Model space
Handle = 147
from point, X=-31319.5480 Y= 0.0000 Z=11220.7042
to point, X=-31319.5480 Y=13619.0682 Z=11220.7042
Length =13619.0682, Angle in XY Plane = 90
Delta X = 0.0000, Delta Y = 13619.0682, Delta Z = 0.0000

Why are the y and z swapping around? Has anyone found this?

 

Hi iwafb

DXF point groups are always expressed in WCS coordinates, the list command
in UCS coordinates.
To translate this points to another coordinate system use 'trans', eg.:
(trans (cdr (assoc 10 a)) (entlast) 1)
translates the startpoint of the line to the current UCS.
For further information around 'trans' search the AutoLISP reference.

Cheers