how to make a list from a set of points

Greetings everyone

i have a set of points

say:

p1 = (x1 , y1 , z1)

p2 = (x2 , y2 , z2)

p3 = (x3 , y3 , z3)

when i use

(setq lst (cons p1 lst) )

(setq lst (cons p2 lst) )

(setq lst (cons p3 lst) )

the final list will looks like ((x1 y1 z1) (x2 y2 z2) x3 y3 z3)

with the list length is 5 not 3 ... ie the third point is included between parenthesis

i usde append instead of "cons" with no hope...

any suggestions ?

thanks in advance

_$ (setq lst (cons '(x1 y1 z1) lst))
((X1 Y1 Z1))
_$ (setq lst (cons '(x2 y2 z2) lst))
((X2 Y2 Z2) (X1 Y1 Z1))
_$ (setq lst (cons '(x3 y3 z3) lst))
((X3 Y3 Z3) (X2 Y2 Z2) (X1 Y1 Z1))

Or just wrap them with the list function:

_$ (list 
 '(x1 y1 z1)
 '(x2 y2 z2)
 '(x3 y3 z3)
)
((X1 Y1 Z1) (X2 Y2 Z2) (X3 Y3 Z3))

_$ (setq lst (cons '(x1 y1 z1) lst))
((X1 Y1 Z1))
_$ (setq lst (cons '(x2 y2 z2) lst))
((X2 Y2 Z2) (X1 Y1 Z1))
_$ (setq lst (cons '(x3 y3 z3) lst))
((X3 Y3 Z3) (X2 Y2 Z2) (X1 Y1 Z1))

 

Or just wrap them with the list function:

 

_$ (list 
 '(x1 y1 z1)
 '(x2 y2 z2)
 '(x3 y3 z3)
)
((X1 Y1 Z1) (X2 Y2 Z2) (X3 Y3 Z3))

it works well ... thanks..

excuse me i have another question and it doesn't worth to open a new thread for it ...

...

i have a selection set "ss1"

i want to select among it's entites the ones which intersect with points p1 and p2

i tried (setq ssj (ssget "F" (list p1 p4) ) ss1)

but it comes with error message :bad point argument

when i use (setq ssj (ssget "F" (list p1 p4) ) ) .. it works well ... but i need only entites from ss1 not all objects...

thanks

i have a selection set "ss1"

i want to select among it's entites the ones which intersect with points p1 and p2

 

i tried (setq ssj (ssget "F" (list p1 p4) ) ss1)

but it comes with error message :bad point argument

Reason that you get the error message is that you cannot provide SS as an argument to the ssget function,

Check Lee Mac's tutorial/reference about ssget (the fence example).

Quoting from there:

(ssget "_F" '((0 0) (1 1)) '((0 . "LINE")))

means..

(ssget "_F" pL ssfL)

Where pL - means point list (list of points)

ssfL - means ssget filter list - assoc list of dotted pairs [optional]

So I'd iterate over the "ssj" and exclude using ssmemb the entities that are not in "ss1", grouping them in "newSS":

(if
 (and
   (setq ssj (ssget "_F" (list p1 p2 p3 p4))) ; I guess you want the fence through the points, not just the endpoints
   (setq newSS (ssadd)) ; create new empty selection set
 )
 (progn ; iterate over the "ssj" and grip the "newSS"
   (repeat (setq index (sslength ssj))
     (setq ent (ssname ssj (setq index (1- index)))) ; nth entity of the selection set
     (if (ssmemb ent ss1) (ssadd ent newSS)) ; if that entity is inside the "ss1", then collect it in "newSS"
   ); repeat
   (sssetfirst nil newSS) ; grip "newSS"
 ); progn
); if

But perfectly only one iteration is enough, if we knew what are the filter criterias for "ss1".

Reason that you get the error message is that you cannot provide SS as an argument to the ssget function,

Check Lee Mac's tutorial/reference about ssget (the fence example).

 

Quoting from there:

 

 

means..

(ssget "_F" pL ssfL)

Where pL - means point list (list of points)

ssfL - means ssget filter list - assoc list of dotted pairs [optional]

 

So I'd iterate over the "ssj" and exclude using ssmemb the entities that are not in "ss1", grouping them in "newSS":

 

(if
 (and
   (setq ssj (ssget "_F" (list p1 p2 p3 p4))) ; I guess you want the fence through the points, not just the endpoints
   (setq newSS (ssadd)) ; create new empty selection set
 )
 (progn ; iterate over the "ssj" and grip the "newSS"
   (repeat (setq index (sslength ssj))
     (setq ent (ssname ssj (setq index (1- index)))) ; nth entity of the selection set
     (if (ssmemb ent ss1) (ssadd ent newSS)) ; if that entity is inside the "ss1", then collect it in "newSS"
   ); repeat
   (sssetfirst nil newSS) ; grip "newSS"
 ); progn
); if

 

But perfectly only one iteration is enough, if we knew what are the filter criterias for "ss1".

.. thanks a lot for your time and good explanation ....the ss1 are only of the type "line" if this make a different

....the ss1 are only of the type "line" if this make a different

Then you could just do this:

(sssetfirst nil (ssget "_F" (list p1 p2 p3 p4) '((0 . "LINE"))))

Ofcourse if you intend only to "grip" the selection set.