Quickie beginning of an investigation into where that information is held:
What Xclipped Xref [which is (entlast) here] has in entity data that it doesn't have before Xclip [rectangular clip]:
(102 . "{ACAD_XDICTIONARY") (360 . <Entity name: 7ed5ac60>) (102 . "}")
But that much remains in entity data after Deleting the Xclipping from it.
What the 360 entry contains with Xclip in effect --
Command: (ENTGET (CDR (ASSOC 360 (ENTGET (ENTLAST)))))
returns:
((-1 . <Entity name: 7ed5ac60>) (0 . "DICTIONARY") (330 . <Entity name: 7ed5ac58>) (5 . "29C") (100 . "AcDbDictionary") (280 . 1) (281 . 1) (3 . "ACAD_FILTER") (360 . <Entity name: 7ed5ac68>))
and after Xclipping is Deleted:
((-1 . <Entity name: 7ed5ac60>) (0 . "DICTIONARY") (330 . <Entity name: 7ed5ac58>) (5 . "29C") (100 . "AcDbDictionary") (280 . 1) (281 . 1))
It's lost the latter parts. So at that level, if there's a 360 entry, there seems to be an Xclip in effect.
Two more levels down in 360 entries with Xclip in effect:
Command: (entget (cdr (assoc 360 (entget (cdr (assoc 360 (entget (cdr (assoc 360 (entget (entlast)))))))))))
returns:
((-1 . <Entity name: 7ed5ac70>) (0 . "SPATIAL_FILTER") (5 . "29E") (102 . "{ACAD_REACTORS") (330 . <Entity name: 7ed5ac68>) (102 . "}") (330 . <Entity name: 7ed5ac68>) (100 . "AcDbFilter") (100 . "AcDbSpatialFilter") (70 . 2)
(10 37.0 8.5 0.0) (10 40.5 19.0 0.0) ;;;;; <-- corners of rectangular clip
(210 0.0 0.0 1.0) (11 0.0 0.0 0.0) (71 . 1) (72 . 0) (73 . 0) (40 . 1.0) (40 . 0.0) (40 . 0.0) (40 . 0.0) (40 . 0.0) (40 . 1.0) (40 . 0.0) (40 . 0.0) (40 . 0.0) (40 . 0.0) (40 . 1.0) (40 . 0.0) (40 . 1.0) (40 . 0.0) (40 . 0.0) (40 . 0.0) (40 . 0.0) (40 . 1.0) (40 . 0.0) (40 . 0.0) (40 . 0.0) (40 . 0.0) (40 . 1.0) (40 . 0.0))
Those could be used in a RECTANGLE command to draw the Xclip boundary. I imagine the boundary of a non-rectangular clip would be contained similarly, but haven't dug into that yet.
Kent Cooper, AIA