I cannot restrict the selection to exactly crossed entities using ssget "c"

[Anonymous]

When using:

(ssget "c" (polar Entity_Insert_Point 1.58825 9)(polar Entity_Insert_Point 1.55334 9)(list (cons 0 "LWPOLYLINE") (CONS 8 "GT_2") (CONS 43 0.25)))

If the area is zoomed to the selection, works as expected, nil in this case. If zoomed to extents, close entities are selected in error. I am sure there is a variable to restrict this behaviour, just not sure which one.

Help appreciated.

[DannyNL]

Aah....my mistake.

In the pre-processing dwg, the coordinate relates to the section.bubble. I'll check and come back.

[hak_vz]

Sorry, my error. Points creating fence should be element of a list. It works with my old version of so it must be supported.

(ssget "F" (list (polar Entity_Insert_Point 1.58825 9)(polar Entity_Insert_Point 1.55334 9))(list (cons 0 "LWPOLYLINE") ) (CONS 8 "GT_2") (CONS 43 0.25))

[DannyNL]

OK, I've looked at the coordinate and the calculated polar points.

Your insertion point is located at the red arrow and the calculated polar points are the yellow line within the red rectangle. As you can see these do not intersect the arced polyline and therefore it will not be selected.

If you only want to select the arced polyline, you'll need to calculate points that will intersect the object. Your SSGET already contains a filter on LWPOLYLINE, so other types will not be selected. And if you want to make sure the selected LWPOLYLINE is arced and not straight, you can add an additional filter with code 42 is not equal to 0.0 to your SSGET.

Example below. The crossing will be made from the insertion point straight up 9mm.

(setq Entity_Insert_Point '(220.537 72.148 0.0))
(setq tst (ssget "c" Entity_Insert_Point (polar Entity_Insert_Point 1.5708 9) '((0 . "LWPOLYLINE")(8 . "GT_2")(43 . 0.25)(-4 . "<>")(42 . 0.0))))

[hak_vz]

(ssget "F" (list (polar Entity_Insert_Point 1.58825 9)(polar Entity_Insert_Point 1.55334 9)(list (cons 0 "LWPOLYLINE") ) (CONS 8 "GT_2") (CONS 43 0.25)))

[DannyNL]

Well, almost OK, but it should be:

(ssget "F" (list (polar Entity_Insert_Point 1.58825 9)(polar Entity_Insert_Point 1.55334 9)) (list (cons 0 "LWPOLYLINE")(CONS 8 "GT_2") (CONS 43 0.25)))

But if the calculated fence points don't intersect the polyline, it still won't be selected.

[Anonymous]

The polyline arc should not be selected, when the drawing is zoomed to its extents, it is added to the selection set erroneously.

A similar check is run for right, up, left and down to establish which block to insert.

[DannyNL · Accepted solution]

OK, now I know what to look for and can confirm with crossing the behavior is strange by selecting the arced polyline when zoomed to extents 

And in that case you can use fence as suggested by @hak_vz

Difference between crossing and fence is that crossing will create a selection rectangle, while fence will use a selection line and therefore is more precise. Although I'm not sure why crossing in this case doesn't work as the selection rectangle shouldn't touch the arced polyline. But fence in this case does work.

(setq Entity_Insert_Point '(220.537 72.148 0.0))
(ssget "F" (list (polar Entity_Insert_Point 1.58825 9)(polar Entity_Insert_Point 1.55334 9)) '((0 . "LWPOLYLINE")(8 . "GT_2")(43 . 0.25)))

[hak_vz · Accepted solution]

Shouldn't it be

(ssget "F" 
          (list (polar Entity_Insert_Point 1.58825 9)(polar Entity_Insert_Point 1.55334 9))
          (list 
               (cons -4 "<and") 
                      (CONS 0 "LWPOLYLINE")
                      (CONS 8 "GT_2")
                      (CONS 43 0.25)
               (cons -4 "and>")
            )
)

In case when all additional criteria apply boolean selector could be omitted?

[DannyNL]

Yes, the AND operator is default and can be omitted in this case.

[Anonymous]

Thank you Guy's, I'd forgotten fences were even a selection option within AutoCAD This has cured the problem, I have a fair amount of back tracking to do.

It would still be nice to know why crossing has an aura that selects entities that shouldn't be selected though!

Thanks again,

owe you a beer!