Topic: Selection between 2 points but excluding any objects on the exact points.

[LSElite]

Hey All

I want to select all objects between 2 points however I want to exclude all objects that are directly under either of the points.

so if the 2 points are midpoints of 2 lines I would like the 2 lines at the beginning and end to be excluded, or if there are multiple objects under the points I want them all be excluded from the selection.

Anyone have any ideas?

Cheers

[Lee Mac]

Option 1: Calculate two points a small distance inside of the two given points, and then obtain a Fence selection using ssget with the two new points.
Option 2: Obtain a Fence selection using ssget with the two points, and a point selection using each point. Remove entities in the Fence selection which are members of the other two selectons.

[LSElite]

I had option 1 in mind but it seemed a bit tedious.
Option 2 is quite clever, perhaps a little slower on execution but i think it will be simpler to program.

Cheers LM

[LSElite]

Hey Lee

Hopefully this is a quick one, how can I select all objects on a point?
Can i do this through point selection ":E", or must I use a window selection a little bigger than the point?

[Lee Mac]

Hopefully this is a quick one, how can I select all objects on a point?
Can i do this through point selection ":E", or must I use a window selection a little bigger than the point?

You could use:

Code: [Select]

(ssget pt)
to select objects which pass through the point 'pt', though, to allow some tolerance you may want to use something like:

Code: [Select]

(ssget "_C" (mapcar '- pt '(1e-3 1e-3)) (mapcar '+ pt '(1e-3 1e-3)))

[LSElite]

I think im going to lose my mind with this one.

So i am trying to make a function from LM's idea but it wont work.
It keeps spitting out:
** Error: too many arguments **

I have a neaking suspicion it has something to do with the view extents so I have been playing with the view window but to no avail.

Anyone have any ideas before I lose my last marble?

Code - Auto/Visual Lisp: [Select]

1. (defun ObjectIdentification (p1 p2 / ss1 ss2 ss3 ct)
2.         (setq SelRange 10)
3.         (command "zoom" "W" p1 p2)
4.         (if (setq ss1 (ssget "_F" (list p1 p2)))
5.                 (progn
6.                         (command "zoom" "o" "p" "")
7.                         (if (setq ss2 (ssget "_C" (mapcar '- pt '(1e-3 1e-3)) (mapcar '+ pt '(1e-3 1e-3))))
8.                                 (progn
9.                                         (repeat (setq ct (sslength ss2))
10.                                                 (setq ss1 (ssdel (ssname ss2 ct) ss1))
11.                                                 (setq ct (1- ct))
12.                                         )
13.                                 )
14.                         )
15.                         (if (setq ss3 (ssget "_C" (mapcar '- pt '(1e-3 1e-3)) (mapcar '+ pt '(1e-3 1e-3))))
16.                                 (progn
17.                                         (repeat (setq ct (sslength ss3))
18.                                                 (setq ss1 (ssdel (ssname ss3 ct) ss1))
19.                                                 (setq ct (1- ct))
20.                                         )
21.                                 )
22.                         )
23.                 )
24.         )
25.         princ ss1
26. )

[Lee Mac]

Code - Auto/Visual Lisp: [Select]

1. (setq ss2 (ssget "_C" (mapcar '- pt '(1e-3 1e-3)) (mapcar '+ pt '(1e-3 1e-3))))

Code - Auto/Visual Lisp: [Select]

1. (setq ss3 (ssget "_C" (mapcar '- pt '(1e-3 1e-3)) (mapcar '+ pt '(1e-3 1e-3))))

You have used variables p1 & p2 in your function, therefore the variable pt will be nil.

Code - Auto/Visual Lisp: [Select]

1. (ssname ss2 ct)

Variable ct will need to be decremented first, as selection set indexes are zero-based.

Code - Auto/Visual Lisp: [Select]

1. (setq ss1 (ssdel (ssname ss2 ct) ss1))

Be careful with this, as ssdel will return nil if (ssname ss2 ct) is not a member of ss1, thereby redefining ss1 to nil.

[LSElite]

LM to the rescue again, Cheers mate. 

Be careful with this, as ssdel will return nil if (ssname ss2 ct) is not a member of ss1, thereby redefining ss1 to nil.

This advice probably just saved me a few hours of programming.
Do you know of any efficient ways of removing one selection set from another or a way of bypassing this problem with ssdel?

[Kerry]

Do you know of any efficient ways of removing one selection set from another or a way of bypassing this problem with ssdel?

Something like this is a bit crude, but it may do the job for you.

Code - Auto/Visual Lisp: [Select]

1.  
2.   (if (and ss1 ss0)
3.     (progn (vl-cmdf "_.Select" ss0 "_Remove" ss1 "")
4.            (setq ss0 (ssget "_P"))
5.     )
6.   )
7.   (if (and ss2 ss0)
8.     (progn (vl-cmdf "_.Select" ss0 "_Remove" ss2 "")
9.            (setq ss0 (ssget "_P"))
10.     )
11.   )
12.   (if (setq sslen (sslength ss0))
13.     (alert (strcat "Selected : " (itoa sslen)))
14.   )
15.  
16.  

[Kerry]

LSElite,
Keep in mind that Lee may be working imperial measurements

His 1e-3
may be different to your 1e-3

[LSElite]

Something like this is a bit crude, but it may do the job for you.

Cheers mate, crude works for me. 

Keep in mind that Lee may be working imperial measurements

His 1e-3
may be different to your 1e-3

Cheers for the heads up, something is givng me some wierd output here, I think that may be it.
To be honest I dont know how the 1e-3 actually works in lisp, is it an exponent or something to do with imperial?
Is there anything I can sub it out for to check if that is whats causing it?

[Kerry]

1e-3 is one unit of measurement with the decimal kicked left 3 places.

added:
Command: (rtos 1e-3 2 9)
"0.001000000"

[LSElite]

1e-3 is one unit of measurement with the decimal kicked left 3 places.

added:
Command: (rtos 1e-3 2 9)
"0.001000000"

Cheers mate, I suspected as much.

I found the bugs, so many dumb mistakes on my part.

here is the what ive got so far:

Code - Auto/Visual Lisp: [Select]

1. (defun ObjectIdentification  (p1 p2 / ss1 ss2 ss3 ct)
2.         (setq osmode (getvar "osmode"))
3.         (command "osmode" "0")
4.         (setq SelRange 10)
5.         (command "zoom" "W" p1 p2)
6.         (if (setq ss1 (ssget "_F" (list p1 p2)))
7.                 (progn
8.                         (command "zoom" "o" "p" "")
9.                         (if (setq ss2 (ssget "_C" (mapcar '- p1 '(0.001 0.001)) (mapcar '+ p1 '(0.001 0.001))))
10.                                 (progn
11.                                         (vl-cmdf "_.select" ss1 "_remove" ss2 "")
12.                                         (setq ss1 (ssget "_P"))
13.                                 )
14.                         )
15.                         (if (setq ss3 (ssget "_C" (mapcar '- p2 '(0.001 0.001)) (mapcar '+ p2 '(0.001 0.001))))
16.                                 (progn
17.                                         (vl-cmdf "_.select" ss1 "_remove" ss3 "")
18.                                         (setq ss1 (ssget "_P"))
19.                                 )
20.                         )
21.                 )
22.         )
23.         (command "osmode" osmode)
24.         princ ss1
25. )

The only downside is it will not detect a line that is running directly under the selection in parallel.

[Kerry]

What is the line length relative to the 2 points ?

Chances are if it passes through either point it will be excluded
... or if it's within 0.001 of either point

[LSElite]

the line just happens to pass directly under the line of selection, it is essentially identical apart from the length. it is a strange it misses it, i guess I just need to find a way to up the tolerance a bit to grab it.