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Dim line behavior

4 REPLIES 4
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Message 1 of 5
Anonymous
280 Views, 4 Replies

Dim line behavior

This one's kind of challenging.

If you change a linear dimension using the grips along an extension line, as
the measured value changes, so does placement of the dimension lines, text
and arrows. It all depends on how much space is available between the
extension lines, the dimtext size, and how the variable "dimfit" is set. For
example, it can be set to either "text only" or "best fit," just to name a
couple.

What I'm wondering is (depending on how you set dimfit, of course), what
controls when, or at what measured value the dimension lines toggle in or
out of the extension lines? What controls when the text toggles out of the
extension lines, and what controls when the dimension lines finally toggle
out to join the text?

In other words, as you resize a dimension, there are a number of "phases."
For example, when the dimension is large, everything fits between the
extension lines. As the dimension is reduced, eventually there isn't enough
room for everything and something is kicked out; the dimension lines and
arrow heads, for example. Then, as you continue to reduce the dimension,
eventually the text is thrown out too.

The reason I'm wondering what controls these "phase" changes, is that they
don't always kick in when I would prefer them too. For example, as you
reduce a dimension, text and/or dimension lines are kicked out way too late.
They look way too cramped in between the extension lines. In some cases, the
dimension line arrow heads are right on top of the text itself so you can't
even read it. In that case, I would like to have the text kick out earlier
so it's legible.

Any help would be greatly appreciated.
4 REPLIES 4
Message 2 of 5
rats
in reply to: Anonymous

It all depends on the reasons for the move as well as the text height offset etc. but if you are moving the dims by the grips then if you want to have the text outside when you have reached a certain distance (and it appears cramped) then you could grip on the text and force that out side. maybe quite not what you were after bu it will do the job.
Message 3 of 5
Anonymous
in reply to: Anonymous

There was an excellent post by KC Jones (who worked for autodesk* at the
time, and worked on dimensions-programming) back on July 12, 1999. I've
paraphrased/copied it, since I can't seem to find it using the search engine
(and they've archived the groups since then), and all I have of it is a
print-out:

It's all in the DIMFIT variable.

DIMFIT = 0, Fit = "Text and Arrows", will keep the text and arrows together.
In tight spaces both the text and arrows will be placed outside.

DIMFIT = 1, Fit = "Arrows" will actually give the arrows priority in the fit
calculation. If there is room enough for the arrows inside, they will be
placed inside. The text will then tend to be placed outside.

DIMFIT = 2, Fit = "Text" gives the text priority and tends to place the
arrows outside.

DIMFIT = 3, Fit = "Best Fit", is very, very similar to DIMFIT =1 in almost
all cases. The only real difference is that the text stays inside as long
as possible, but when there is no room the text will pop out and the arrow
will dive back in for as long as there is enough room for them. So the text
and arrows do a two-step trying to keep as much stuff inside as possible.
(and if by chance the text is shorter than the two arrows, the dance is
inverted. But this is rare.)

****end paraphrase/copy****

Of course, you probably already know what setting DIMFIT to 4 and 5 do. Do
you?

Does this help?

--
Joshua Tapp ( josht@scm-ae.com )
Designer/Intern - Architecture Group - SCM Consultants, Inc. -
http://www.scm-ae.com - A part of Infrastructure Northwest Group -
http://www.ttinw.com - Division of Tetra Tech, Inc. - http://tetratech.com

Glenn Dietel wrote in message
news:ef2feb9.-1@WebX.SaUCah8kaAW...
> This one's kind of challenging.
>
> If you change a linear dimension using the grips along an extension line,
as
> the measured value changes, so does placement of the dimension lines, text
> and arrows. It all depends on how much space is available between the
> extension lines, the dimtext size, and how the variable "dimfit" is set.
For
> example, it can be set to either "text only" or "best fit," just to name a
> couple.
Message 4 of 5
Anonymous
in reply to: Anonymous

Thanks for your two responses, they're very helpful, but I don't think I
really nailed down what I'm after in my first posting.

I realize how dimfit affects dimensions, but what I'm really wondering is
what controls exactly when a dimension changes phases.
For example, as I reduce a linear dimension, at first everything is inside
the extension lines. Then, as soon as the measured dimension gets to exactly
.400, for example, the dimension lines kick out. Then as I continue to
reduce it, the rest will kick out at another particular value. What decides
these paticular values?

In addition to dimfit and dimtext size, it somehow also depends on the
location of the text between the extension lines. I noticed that wherever
the text is positioned, the dimension will usually undergo a "phase change"
as soon as you move the extension line to the middle of the text, wherever
it happens to be. But this isn't always the case.

To best illustrate the problem, I urge you to try a little experiment on
your system. Start a new drawing and create a dimension, with a decimal
precision of, let's say, 3 places. Zoom in on it and play around with it.
Try resizing it and, taking into account how you have dimfit set, try to
identify why AutoCAD invokes the various phase changes at certain particular
values. Where do these particular values come from? Then move the text
closer to one of the extension lines and try it again. Good luck trying to
nail down any rhyme or reason to it's behavior. If you can figure out the
way it works, please let me know so I can intelligently choose a dimfit
setting and get my dimensions to come out right.

True, if you don't mind playing around with it for long enough and moving
the text around enough you can usually get what you want, but sometimes it's
just way too much hassle than it seems it should be.

Thanks again!
Message 5 of 5
Anonymous
in reply to: Anonymous

> I realize how dimfit affects dimensions, but what I'm really wondering is
> what controls exactly when a dimension changes phases.
> For example, as I reduce a linear dimension, at first everything is inside
> the extension lines. Then, as soon as the measured dimension gets to
exactly
> .400, for example, the dimension lines kick out. Then as I continue to
> reduce it, the rest will kick out at another particular value. What
decides
> these paticular values?

It depends upon the arrow size and the text size. Autodesk set it to some
pre-determined amount, based upon those two sizes (I believe, however, I'm
not Autodesk). It's all in a formula or algorithm. The variables are those
two sizes, and the actual distance being dimensioned.

> In addition to dimfit and dimtext size, it somehow also depends on the
> location of the text between the extension lines. I noticed that wherever
> the text is positioned, the dimension will usually undergo a "phase
change"
> as soon as you move the extension line to the middle of the text, wherever
> it happens to be. But this isn't always the case.

Also, you have to consider whether or not the text is in the home position.
Certain things don't work the same if it's not (like the \X which means it
puts the next bit of text below the dim line). You have to play around with
dimensions, and figure it out for yourself. I'm architectural, so I use
feet and inches (no decimals), so certain things that affect me don't
necessarily affect you.

> True, if you don't mind playing around with it for long enough and moving
> the text around enough you can usually get what you want, but sometimes
it's
> just way too much hassle than it seems it should be.

I agree. I still play around with them and make them into what I want them
to be, just to keep them associative. As far as I understand, there's even
more control in A2K. I do know that DIMFIT was split into two different
commands, of which I don't remember at the moment. I don't have A2K, so I
can't tell you.

--
Joshua Tapp ( josht@scm-ae.com )
Designer/Intern - Architecture Group - SCM Consultants, Inc. -
http://www.scm-ae.com - A part of Infrastructure Northwest Group -
http://www.ttinw.com - Division of Tetra Tech, Inc. - http://tetratech.com

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