AutoCAD - Formula

Formula

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Category: EN
Forum Name: AutoCAD
Forum Description: Discussion about AutoCAD and AutoCAD LT, viewers, DWG and DXF formats, Design Review, AutoCAD web, Drive, add-ons
URL: https://www.cadforum.cz/forum_en/forum_posts.asp?TID=4710
Printed Date: 05.Sep.2026 at 22:34

Topic: Formula

Posted By: shaikh
Subject: Formula
Date Posted: 04.Nov.2010 at 06:58

Dear All
If we want a scale 1:20 then through scale command we only give 20
so after this if we have line=100 its length will be 2000.But the question is that I want the scale 20 times to decrease.For this how much scale I will give and what is the formula to calculate this.Please guide me in this matter.

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taqqi

Replies:

Posted By: linhoreka
Date Posted: 04.Nov.2010 at 14:42

Very easy. The display of the dimension is control by 2 variables: Dimscale and Dimlfac. Dimscale is the scale of the text and arrows. The Dimlfac (dimline factor) control the dimline value. With Dimlfac = 20, the line of 100 length would be dim as 2000. With Dimlfac = 1/20 = 0.05, the line of 100 length would be dim as 5.

Here is 2 useful lisps to control these 2 variables, avoiding create new dimstype each time you want to change their values:

;1. Copy these following lisp lines (in blue text) to an empty lisp file. Save it in any name as you like

;2. Load the file to AutoCAD (better put them in StartUp list if you find it is useful)

;In AutoCAD command line: type "dsc" for Dimscale setting, "df" for DimlFac setting command

;Cheer :)

;DSC AND DF COMMANDS FOR ADJUSTING SILENTLY DIMSCALE AND DIMLFACT VARIABLES

;++++++++ DF DIMLFAC++++++++++++

(defun C:df (/ dimlf odf)

(setq odf (getvar "dimlfac"))

(setvar "cmdecho" 0)

(prompt (strcat "The current Dimlfac is " (rtos odf 2 5)))

(initget 128)

(setq dimlf (getreal "\nEnter DimlinearFactor <or press any keyboard to get dimension style from object> "))

(if dimlf

(if (numberp dimlf)

(setvar "dimlfac" dimlf)

(restoreDimstyle)

)

(princ)

);end defun

;++++++++DSC DIMSCALE+++

(defun C:dsc (/ dimsc ods)

(setvar "cmdecho" 0)

(setq ods (getvar "dimscale"))

(prompt (strcat "The current Dimscale is " (rtos ods 2 5)))

(initget 128)

(prompt "\nDimscale standard value should be one of the following values: 1, 2, 5, 10, 20, 25, 50, 100, 200, 500, 1000, 2000 ...")

(Setq dimsc (getreal (strcat "\nEnter the Dimlinear Scale <" (rtos ods 2 5) "><or press keyboard to get the dimension style from object> ")))

(if dimsc

(if (numberp dimsc)

(setvar "dimscale" dimsc)

(restoreDimstyle)

)

(setvar "LTSCALE" (getvar "DIMSCALE"))

(princ)

);end defun

(defun restoreDimstyle (/ dimlf dimsc e el en)

(setq e (car(entsel)))

(if (null e)(exit))

(setq

el (entget e)

en (cdr(assoc 0 el))

)

(if (or (= en "DIMENSION")(= en "LEADER"))

(progn

(command "-dimstyle" "restore" "" e)

(graphscr)

)

(prompt "No dimension selected")

)

(setq dimlf (getvar "dimlfac")

dimsc (getvar "dimscale"))

(prompt (strcat "\nThe current Dimlfac is " (rtos dimlf 2 5)))

(prompt (strcat "\nThe current Dimscale is " (rtos dimsc 2 5)))

(princ)

);end defun

Posted By: CarlB
Date Posted: 04.Nov.2010 at 23:55

If I understood your question...

If you want to decrease a scale by a factor of 20, you have 2 ways you could enter this on the command line;

1- use a calculator, 1/20 =.05. So enter ".05" for the scale

2-You can enter ratios of whole nubers on the command line; so for the scale enter "1/20"

But....the golden rule of cad drawings is to draw ebverything real worls scale. Its's only when you put drawing to paper (or pdf) that you need a drawing scaled, so you handle this with plot scales, or better by plotting from paperspace, with a scaled viewport showing modelspace objects.

Posted By: shaikh
Date Posted: 06.Nov.2010 at 12:40

Thanks a lot for reply me and your reply is Ok,but my question is that if we have DWG in model space of different sections and these sections scale is 1:20 then we give scale factor in DIM type 0.400.So how it will come because I have a DWG like that.I will wait for your reponse.

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taqqi