Editing a single attribute via LISP

I am trying to write a LISP routine that controls revisions of drawings. Our drawing title block has about 20 attributes in it. I want the routine to edit just one of the attributes (namely, the revision letter) and not touch the rest. Is there any way to do this?

Any help will be greatly appreciated,

Cheers

Simon.

 

Do you want to try and code it yourself ?
You need to grab the block insert (your title block), dig into the attributes, find the 'tag' name of the attribute, and replace the 'value' of that attribute using entmod / entupd. Tricky part is drilling down through the attributes - and - checking the 'existing' value (say it is rev B) - to make it a C.

Bob

 

If you don't want to tackle it, you could .zip a drawing with the Title Block and attach to E-Mail to:

remove the nospam + .
I will generate the Lisp, and post it here.
(no charge)

Bob
www.bobscadshop.com

 

here is a quick and dirty program without error checking.
Change values in "" to your specs

(setq TitleBlockName "YourTitleBlockName")
(setq AttributeName "YourAttributeName")
(setq NewAttributeValue "NewAttributeValue")
(if (setq SS (ssget "X" (list (cons 0 "INSERT") (cons 2 TitleBlockName))))
(progn
(setq EG (entget (ssname SS 0)))
(setq EN (entget (entnext (cdr (assoc -1 EG)))))
(while (and (/= (strcase (cdr (assoc 2 EN))) (strcase AttributeName))
(/= (cdr (assoc 0 EN)) "SEQEND"))
(setq EN (entget (entnext (cdr (assoc -1 EN)))))
)
(if (= (strcase (cdr (assoc 2 EN))) (strcase AttributeName))
(progn
(setq EN (subst (cons 1 NewAttributeValue) (assoc 1 EN) EN))
(entmod EN)
(entupd (cdr (assoc -1 EG)))
)
)
)
(princ)
)