Dimension drawing standardization completed

Discussions about the development of the TechDraw workbench
tpavlicek
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Re: Dimension drawing standardization completed

Postby tpavlicek » Thu Sep 26, 2019 12:11 pm

Exactly - the TechDraw preference serves as a default for a newly created dimension. Once it is created, use the "Standard And Style" resp. "Rendering Extent" properties in each dimension's "View" tab to modify the selected dimension. I will update the Wiki documentation pages very soon.

Tomas
tpavlicek
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Re: Dimension drawing standardization completed

Postby tpavlicek » Fri Sep 27, 2019 3:26 pm

Hi to all,

I have just updated the Wiki page concerning the Dimension properties - https://www.freecadweb.org/wiki/TechDra ... ion_Length

If you are interested, please take a look and eventually let me know, if something is not clear or needs to be reformulated.

Kind regards,

Tomas
aapo
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Re: Dimension drawing standardization completed

Postby aapo » Tue Oct 15, 2019 1:07 pm

Hi!

I noticed that using the new model here, the ISO dimension lines always touch the drawing, whereas the ANSI dimension lines leave a small gap to the drawing. Would it be possible to get this small gap to the ISO dimension lines, too? At least one drafting example I found in the internet also had this gap with ISO dimensions. If it would be selectable per-dimension, that'd be even greater.

https://www.slideshare.net/khattakgreat ... b-ali-khan
engineering-drawning-graphicsintroductionlettering-and-dimensionlecture-23-by-engr-zohaib-ali-khan-21-638.jpg
engineering-drawning-graphicsintroductionlettering-and-dimensionlecture-23-by-engr-zohaib-ali-khan-21-638.jpg (16.83 KiB) Viewed 649 times
DimensioningSample-highlighted.png
DimensioningSample-highlighted.png (137.83 KiB) Viewed 647 times
chrisb
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Re: Dimension drawing standardization completed

Postby chrisb » Tue Oct 15, 2019 9:49 pm

Although my standards book doesn't say it explicitely, all ISO drawings I have seen have these helperlines (= direct translation from german) touching the object. I'm afraid it would be no longer ISO if this was changed. The fact that there exists some drawing in the internet doesn't help much - it can be wrong; it has to be in the standard.
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wandererfan
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Re: Dimension drawing standardization completed

Postby wandererfan » Wed Oct 16, 2019 12:12 am

aapo wrote:
Tue Oct 15, 2019 1:07 pm
I noticed that using the new model here, the ISO dimension lines always touch the drawing, whereas the ANSI dimension lines leave a small gap to the drawing. Would it be possible to get this small gap to the ISO dimension lines, too? At least one drafting example I found in the internet also had this gap with ISO dimensions.
My understanding is that ASME requires the gap and ISO recommends (but doesn't require?) that there be no gap. I don't have either official spec handy to check.
If it would be selectable per-dimension, that'd be even greater.
Why would you want dimensions on the same page to use different rules?
aapo
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Re: Dimension drawing standardization completed

Postby aapo » Wed Oct 16, 2019 6:12 am

wandererfan wrote:
Wed Oct 16, 2019 12:12 am
Why would you want dimensions on the same page to use different rules?
I was thinking that sometimes it would be more clear to have the helper lines not touch the drawing with the ISO drafting also, in cases where the drawing has small details that the helper lines would clutter. Not a very good reason, I admit, as it'd probably better to use a Detail View anyway for the drafting.

In general, I agree it is better to have this new fully standard-compliant drafting. So far, it's been much much better for the FreeCAD TechDraw drawings I've made, when compared to the old non-standard-compliant drafting in TechDraw.
reox
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Re: Dimension drawing standardization completed

Postby reox » Wed Oct 16, 2019 9:16 am

AFAIK the "relaxed" drawing style is also used by other CAD programs to create ISO conformal drawings, but dont quote me on that ;)
I'll try to look this up, maybe I can find it somewhere...
chrisb
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Re: Dimension drawing standardization completed

Postby chrisb » Wed Oct 16, 2019 9:38 am

The ISO idea is not to have the helper lines going from the dimension in the direction of the workpiece. It talks about extending the workpiece. I would derive from that, that there should be no gap in between.
reox
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Re: Dimension drawing standardization completed

Postby reox » Wed Oct 16, 2019 11:09 am

chrisb wrote:
Wed Oct 16, 2019 9:38 am
The ISO idea is not to have the helper lines going from the dimension in the direction of the workpiece. It talks about extending the workpiece. I would derive from that, that there should be no gap in between.
On the other hand, as far as I remember it, the most important rule is that a drawing must be in such a way, that it is universal and understandable without the possibility of interpretation. Having a small space between the workpiece and the helper line should in my opinion not lead to confusion. (Although, there might be certain edge cases where it does)
Actually it improves readability in my opinion - but thats just my personal interpretation.
Obviously, if you need to provide drawings to some company and there is room for interpretation of the drawing due to the relaxed drawing style, you will get in trouble.
chrisb
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Re: Dimension drawing standardization completed

Postby chrisb » Wed Oct 16, 2019 7:02 pm

Personally I too would prefer a tiny gap, but I prefer even more to do it the standard way. Without the gaps we have it ISO conformant and in a format which is used whereever ISO is used. Nobody will object that it may not be conformant.

To have it conformant with using loopholes where the standard may be unprecise cannot be a solution. It may be nicer, easier to use, smell better. But that's not why we use standards.