entsel and then nil

How do I specify an action based on wheather or not an object exists at a given point. For example, first step, if an object does not exist at 0,0,0, then I want to set 0,0,0 as pt1 for the rest of my lisp. If an object do exist, the next point, I want it to be 16,0,0 and have that co-ordinate set as my pt1 for my lisp. If an object exists at 16,0,0, then I want to use 32,0,0 and so on. Basically the first point that creats a nil, I want it to become my pt1.
Also, eventually when i travel too far the right I'm going to be inserting a negative Y co-ordinate, but I haven't decided what my extents are going to be.
tnx
kpennell

 

To check for an object at 0,0:
(setq pt1 (list 0.0 0.0 0.0))
(setq pt2 pt1)
(setq ss (ssget "c" pt1 pt2))
(if ss
(progn
(........there was something there..do your thing)
)
)
To increment the next point..
(setq pt1 (+ (car pt1) 16.0)(+ (cadr pt1) 0.0)))

Bob

 

Hi kpennell

Do you use a specific object like a block or so?

Cheers

 

Another way:

(setq pnt '(0 0 0))
(while (not ent)
(setq ent (nentselp pnt))
(if (zerop (car pnt))
(setq pnt (append (list (+ (car pnt) 16)) (cdr pnt)))
(setq pnt (append (list (* (car pnt) 2)) (cdr pnt)))
)
)

--
Ken Alexander
Acad2004
Windows XP

"We can't solve problems by using the same kind
of thinking we used when we created them."
--Albert Einstein

at a given point. For example, first step, if an object does not
exist at 0,0,0, then I want to set 0,0,0 as pt1 for the rest of my
lisp. If an object do exist, the next point, I want it to be 16,0,0
and have that co-ordinate set as my pt1 for my lisp. If an object
exists at 16,0,0, then I want to use 32,0,0 and so on. Basically the
first point that creats a nil, I want it to become my pt1.

inserting a negative Y co-ordinate, but I haven't decided what my
extents are going to be.

 

There is a template that is inserted based on my variable p1, that if there is nothing at 0,0 (p1), then insert the template at 00 (p1), but if a template already exists there (i.e. 0,0-p1) then insert it at 16,0, and still have that co-ordinate as p1 for the rest of my Lisp
Is that clearer

 

Hmmm... template - you mean a block do you?

In case of a block you can use this function:
;
; == Function GetBlockAtPoint
; Returns the block entity at given point.
; Argumente [Type]:
; Pnt = Insertion point of block '(X Y Z)

• 
  ; Pre = Precision to select the insertion point [REAL]
  ; Return [Type]:
  ; > Block ename [ENAME]
  ; nil if no block found at the point
  ; Notes:
  ; None
  ;
  (defun GetBlockAtPoint (Pnt Pre / CurSet LolPnt UprPnt)
  (setq LolPnt (mapcar '- Pnt (list Pre Pre 0.0))
  UprPnt (mapcar '+ Pnt (list Pre Pre 0.0))
  CurSet (ssget "X" (list
  '(0 . "INSERT")
  '(-4 . ">,>,*") (cons 10 LolPnt)
  '(-4 . "<,<,*") (cons 10 UprPnt)
  )
  )
  )
  (if CurSet (ssname CurSet 0))
  )
  If the object is not a block, you've to change the filter to the corresponding
  entity name. Does not work with entities they have multiple 10 codes like
  Plines. Consider the 3D point for the Pnt argument.
  
  Cheers

 

this casues my session to lock-up, 2000

 

and this one has too few arguments

 

Did you call it correctly ?
(defun GetBlockAtPoint (Pnt Pre / CurSet LolPnt UprPnt)
In the call, you need to supply (2) items. (Pnt Pre /...
Implies a Point e.g. '(0.0 0.0 0.0)
and a Pre(cision) e.g. (setq Pre 0.01)
Then call it this way.

(setq Pre 0.01 Pnt (list (0.0 0.0 0.0)))
(GetBlockAtPoint Pnt Pre)

Bob

 

(defun check-obj(/ ent)

(setq pt1 '(0.0 0.0 0.0))
(setq ent (nentselp pt1))
(while (not ent)
(setq pt1 (list (+ 16.0 (car pt1)) 0.0 0.0))
(setq ent (nentselp pt1))
)
(princ)
)

Try this.
Tim

 

Or try:
;; Initial Point to test..
(setq ss nil ip nil)
(setq pt1 (list 0.0 0.0 0.0))
(setq pt2 (+ (car pt1) 0.1)(- (cadr pt1) 0.1)))
(setq ss (ssget "c" pt1 pt2))
(if (= ss nil)
(setq ip pt1)
);if
(while ss
(progn
(setq pt1 (+ (car pt1) 16.0)(+ (cadr pt1) 0.0)))
(setq pt2 (+ (car pt1) 0.1)(- (cadr pt1) 0.1)))
(setq ss (ssget "c" pt1 pt2))
(if (= ss nil)
(setq ip pt1)
);if
);progn
);while
(princ)
(prompt "\nNew Insert Point =")
(if ip (princ ip))

Bob

 

kpennel

Would it be impolite to expect think for one's self?

Cheers

 

yes it would be
you are mistaking me for someone who leaches all this lisp information that I am so gratious of receiving. My apologies for my ignorance, as I am not near as advanced in programing as most of you blokes are.
Sincerly in not trying to offend anyone here
kpennell

 

maybe if I word it this way

setq p1
where p1 equals the FIRST point (in a series of points) that does NOT contain an object at that point. The first point in that series of points is 0,0 and the X co-ordinate for the series of points thereafter is a multiple of 16.

(defun getvars ()
here is where I'm trying to define p1
;defun
________________________________________________________________________________________________________________

( defun insert ()
( command "_SCINSERTSTIFFENERS" p1 )
);defun insert
________________________________________________________________________________________________________________

( defun getvars_again ()
( setq FN ( getvar "dwgname" ))

( setq pt2 ( list 0.9369 10.3109 0.0 ))
( setq pt3 ( list 2.0 10.3108 0.0 ))
( setq txt ( ssget "C" pt2 pt3 ))
( if txt
( progn
( setq ent ( ssname txt 0 ))
( setq ent ( entget ent ))
( setq STK ( cdr ( assoc 1 ent )))))

and the order comes from

( getvars )
( insert )
( command "ucs" "n" p1)
( command "zoom" "window" "-0.5,-0.5" "16,11")
( command "-osnap" "end" )
( command "-layer" "s" "0" "")
( getvars_again )

 

No takers?

 

Did you try Tim's?

--
Ken Alexander
Acad2004
Windows XP

"We can't solve problems by using the same kind
of thinking we used when we created them."
--Albert Einstein

 

(defun check-obj(/ ent)

(setq pt1 '(0.0 0.0 0.0))
(setq ent (nentselp pt1))
(while (not ent)
(setq pt1 (subst (+ 16.0 (car pt1)) (car pt1) pt1))
(setq ent (nentselp pt1))
)
(princ)
)

This will return the point (pt1) that doesn't have an object there. If an object exist and (0,0,0) then pt1 is (0.0,0.0,0.0), if not then it adds 16.0 to the x value until it hits something.

Tim

 

What happens if nothing is found?
maybe an upper counter limit to prevent infinite loop in empty dwg?

object exist and (0,0,0) then pt1 is (0.0,0.0,0.0), if not then it adds 16.0
to the x value until it hits something.

 

I'm running AutoCAD 2000
When I run your lisp, it locks up on me. What version are you running

 

I'll try again. If something is found at p1, then go to the next point. (i.e. a multiple of 16 for the x co-ordinate) if nothing is found at p1 well then I want to do bunch of things based on the point that have nothing existing and re-define p1