Add or subtract a number from a dimension

[tedg]

This whole post has really gotten out of hand although I find it really amusing. 1st of all not all projects are cookie cutter perfect nor does everyone have the same work flow. Most places have reasons for what they do, and if not they are on really thin ice. 2nd when you start using always and never the one thing you can be sure of sooner or later you will be wrong. I have used offset linework for clarity which was identified as such and clearly stated. 3rd dims are just text at the basic level so if you are confident enough to be able to edit a dimension I'm not sure I want the liability of telling you how to do it. This really basic stuff.

I wouldn't say this has gotten "out of hand" I don't know why you would say that, most of us really want to know the specifics and why you would want to/have to do this.
There's a reason AutoCAD (and CAD programs) is designed to be accurate, in most cases, it's best-practice to use it that way to avoid issues, not to mention it's actually more work to do it inaccurate.

At least in MY case, wanting to know the process to maybe help in a more refined way other than overriding dimensions, but it seems that's what the OP needs to do.
I wouldn't call this "basic stuff", it's a trick for that particular shop they need to do, but not any procedure I've seen/used in over 25 years in the business, but I do Arch and Struct, this is a Civil 3D thread so I wouldn't know if that is done a lot.

I think Tom's reply is the best method if it works (which it looks like it would)

Found https://forums.autodesk.com/t5/visua...342887#M326867
with a quick Google search https://www.google.com/search?q=dime...AutoCAD%20Lisp

[cadtag]

yeah, the PM asking that is opening up a massive liability hole for the company. I can pretty much guarantee that mixing accurate representation with deliberately in-accurate representations is going to put him on the losing side of a lawsuit. One that may well end up costing them their license.

[BlackBox]

Found https://forums.autodesk.com/t5/visua...342887#M326867
with a quick Google search https://www.google.com/search?q=dime...AutoCAD%20Lisp

Here's a quick modification to the linked code from Tom's apt post:

(defun c:-D (/ ) (_AddSubtractDim -1.5))
(defun c:+D (/ ) (_AddSubtractDim 1.5))
;;;--------------------------------------------------------------------;
(defun _AddSubtractDim (addon / dimss c ddata); = Dimension Text: Add Constant value
  (setq
;;;    addon (getreal "\nConstant value to add to text of selected Dimension(s): ")
    dimss (ssget ":L" '((0 . "DIMENSION")))
    c -1
  )
  (repeat (sslength dimss)
    (setq
      ddata (entget (ssname dimss (setq c (1+ c))))
      ddata
        (subst
          (cons 1 (rtos (+ (cdr (assoc 42 ddata)) addon) 2 2)); <-- adjust mode/precision as desired
          (assoc 1 ddata)
          ddata
        )
    )
    (entmod ddata)
  )
  (princ)
)

If not already done so, it might make sense to have disparate layers for those you're reducing vs those you're increasing. Just to make it easier to select similar & invoke -D or +D, etc.

Cheers

[rmk]

how do you invoke this? I copied the code and loaded it, but I can't seem to get it to work.
gives me "unknown command".

[Opie]

What command did you type after loading it?

[rmk]

_AddSubtractDim

[Opie]

That is not a command line routine as defined in the code provided by BlackBox. To determine command line routine names, look at routines that are defined using the (defun c: prefix. The string following the colon ":" is the name of the command.

For the code posted by BlackBox, the two command line routines are "-D" and "+D". These two commands will subtract or add 1.5 to the overall value of the selected dimensions, respectively.

[rmk]

Thanks Opie.