Multiple Selection Sets 'Intersection'

[Steven P]

So I can join 2 selection sets together, loop through one selection set and ssadd each item as it goes

(simple example set 1: 1, 2, 3,  set 2: 4 5 6 -> 1, 2, 3, 4, 5, 6).

 

is there a nice way to create a selection set that is the intersection of 2 selection sets - that is if an entity is in both then retain it, otherwise discard it

(simple example set 1: 1, 2, 3, set 2: 2, 3, 4 -> 2, 3 but using selection sets)

 

I could do something with (ssmemb .....) but wondered if there was anything a bit cleverer

 

ta

[mhupp]

With comparing you have to pick the long list. Made a simple function that will output the entity names that are in both. just feed it the selection set names.

 

 

Then its just ssadd to an new selecton set.

 

(setq sspoly (ssget))
(setq ss (ssget))
...
(setq ssb (ssadd))
(setq lst (MH:SSI SSpoly SS))
(while lst
  (ssadd (car lst) ssb)
  (setq lst (cdr lst))
)

 

 

SSI.lsp

Edited August 13, 2023 by mhupp
Updated Code

[Steven P]

Thanks - I'll give that a go, should just fit into what I have nicely too

[mhupp]

oops put a not in the if statement so it was removing the ones that it should be keeping.

Edited August 13, 2023 by mhupp

[Steven P]

A quick test cut down the time to do what I was doing from 12 to 4 seconds so a big improvement - barely time to get a drink, but short enough for me to stop wondering if it was all going wrong though (but overall a mornings work to 4 seconds is acceptable).

 

Cheers