Expert: Alan Zube - 6/9/2009

Question
QUESTION: i want to dimension an 3 point arc with its angle on top and arc length below it in a single stroke(just like a simple angular dimension i give it should show arc length below that angle)

ANSWER: I did not know how to do this myself, so I went to a users group archive and found this explanation. I tried it and it worked for me. I think you would need AutoCad 2006 or newer.

Suppose we have an arc in a drawing. And we want to
measure the length of the arc. We want to add the
length to the drawing.

This is how we do it. We click on Dimension in the menu
bar and on Arc Length in the pull down menu. This
prompt is displayed:

Select arc or polyline arc segment:

We select the arc that we have got. After the selection
of the arc this prompt is displayed:

Specify arc length dimension, or [Mtext/Texct/Angle/
Partial/Leader]:

Between the square brackets are the options that we've
got. I'm not going into the options. I just want to
pick a point for the arc length dimension.

As I move the cursor. You can see that the length is
already displayed. There is number. And there is also a
symbol. The arc length symbol.

I must tell something more. I must tell about the
number and I must tell about the arc symbol. We can
change it if we want.

Open the Dimension Style Manager. We can create out own
dimension style or we can modify the existing dimension
style.

Let's modify the existing dimension style. We click on
the Modify button. The Modify Dimension Style dialog
box is displayed.

The dialog box has got seven tabs. We click on the
Arrows and Symbols tab. Now we can set how the arc
length symbol is displayed.

In the dialog box is the Arc length symbol area. In the
area there are three options. The following three
options:

- Preceding dimension text
- Above dimension text
- None

You can have the arc length symbol placed before the
length of the arc. Or preceding the length of the arc.
Or you can have it above the length of the arc.

You can also select that no arc length symbol is
displayed.

The number gives the length of the arc. We can do
something with the number of decimals in the length.
Click on the Primary Units tab.

You'll find the Linear dimensions area. Behind
Precision you can set what precision is to be used. No
decimal places or a number of places.

The units of the length. That depends on what units
have been selected for the drawing. You could change it
over the Units command.


About the author:

Jos van Doorn. Has written many AutoCAD articles. Find
them here:

http://autocad-articles.blogspot.com/

Bio:

Jos van Doorn. AutoCAD specialist and AutoLISP
programmer. Also writer AutoCAD books and AutoCAD
articles. Find them here:

http://autocad-articles.blogspot.com/

---------- FOLLOW-UP ----------

QUESTION: Dear sir,
I am one of professional user of an cad and using 2007/08 version
what happens while detailing,in case of circular object
we need to give its angle dimension and arc length based on some specific radius below it,for this i have to calculate it manually

what i need is, while giving an angle dimension the arc length should appear below it,as an alternate dimension,
it happens in case of linear dimension but no provision for the angular dimension.
i am attaching the sketches pls refer.
THE FORMAT IS FIX AS PER ATTCHED DRAWING

i will be very much thank full to you if you can do this.

Answer
The only way know to do this is to write your own AutoLisp application. I don't know HOW to do it but I know it can be done. I am not an expert in AutoLISP.

This website has the AutoLISP application you can download:
http://www.ellenfinkelstein.com/AutoCAD_tips_dimension_arc_length.html

If that doesn't work I would contact Jos van Dorn and see if he has more information.

Sorry I can not be of more assistance.