Move block to Z co-ord

[Aubrey.kieren]

Please help! I'm very new to lisp.
I found this routine a few days ago on the AutoDESK forums, it looks for the "top attribute"(?) I assume this means the first attribute in the list?
I cannot for the life of me work out how to change it to search for a "named" attribute in a block that I wish to use (attribute name is "INVERT").
I would be most grateful if someone could tell me how to to do this! It would save me SOOOO much time!

Thanks,
..::KIEREN::..



;;;C:bel changes a blocks z coordinate to the elevation listed in the top attribute ;
;;;----------------------------
(defun C:bel()
(setq ss (ssget)
ucsf (getvar "ucsfollow"))
(if (/= ss nil)
(progn
(setq ssl (sslength ss))
(setvar "ucsfollow" 0)
(if (/= 1 (getvar "worlducs"))(setq wucs 0)(setq wucs 1))
(command "ucs" "")
(setq numchg ssl
n ssl
newss (ssadd))
(while (> n 0)
(setq n (1- n)
blk (ssname ss n))
(setq ent (vlax-ename->vla-object blk))
(setq atts (vla-getattributes ent))
(setq temp (vlax-variant-value atts))
(setq elem1 (vlax-safearray-get-element temp 0))
(setq el (atof (vla-get-textstring elem1)))
(command "CHANGE" blk "" "P" "E" el "")

);end while
(setq ssl (sslength newss)
n ssl)
(setq txt "block(s) raised to elevation.")
(if (/= numchg 0)
(progn
(print numchg)
(princ txt))
(prompt "No blocks selected."))
)
(prompt "Empty selection set."))
(if (= 0 wucs)(command "ucs" "p"))
(setvar "ucsfollow" ucsf)
(princ)
);end defun

[stig.madsen]

Something like this maybe?

(defun C:bel (/ att atts blk el ent n numchg ss ucsf wucs)
  ;; we want to make sure the selection holds blocks
  ;; with attributes as not to run into an empty safearray
  (setq ss   (ssget '((0 . "INSERT")(66 . 1)))
        n    0
        numchg 0
        ucsf (getvar "ucsfollow")
  )
  (if ss
    (progn
      (setvar "ucsfollow" 0)
      (if (/= 1 (getvar "worlducs"))
        (setq wucs 0)
        (setq wucs 1)
      )
      (command "ucs" "")
      (repeat (sslength ss)
        (setq blk (ssname ss n)
              n   (1+ n)
        )
        (setq ent (vlax-ename->vla-object blk)
              atts (vla-getattributes ent)
        )
        (foreach a (vlax-safearray->list (vlax-variant-value atts))
          (and (= (vla-get-tagstring a) "INVERT")
               (setq att a)
          )
        )
        (cond (att
               (setq el (atof (vla-get-textstring att)))
               (command "CHANGE" blk "" "P" "E" el "")
               ;; recording actual changes should happen
               ;; here - we just assume it went well
               (setq numchg (1+ numchg))
              )
        )
      ) ;_ end repeat
      ;; reporting 0 changes is also good information
      (princ (strcat (itoa numchg) "block(s) raised to elevation."))
    ) ;_ end progn
    (prompt "Empty selection set.")
  ) ;_ end if
  (if (= 0 wucs) (command "ucs" "p"))
  (setvar "ucsfollow" ucsf)
  (princ)
)

[Aubrey.kieren]

Just like that!

Thank you,
..::KIEREN::..

[stig.madsen]

Darn it, just realized I made an all too common mistake .. please substitute the line

(setq numchg (1+ numchg))

with
(setq numchg (1+ numchg) att nil)

[Aubrey.kieren]

Thanks for that, but just for my info, what difference would that change make, and why should it need to be changed?

..::KIEREN::..

[stig.madsen]

If the loop finds an attribute with the tag "INVERT", it'll point the variable att to it. If it runs into a block that does not contain the attribute, it will already have att pointing at an attribute - a wrong attribute in a wrong insert. So it needs to be cleared before searching next insert.

[Aubrey.kieren]

Cheers! Thanks for the help!