About angular dimension tolerances in TechDraw

[aapo]

Hi!

Currently, when putting tolerances for FreeCAD TechDraw angular dimensions, TechDraw places the tolerance values between the angle value and the degree sign, which I feel is not optimal for readibility.

20200820_FreeCAD_TechDraw_Angular_Tolerance_01.png (26.11 KiB) Viewed 1264 times

Moreover, at least this document https://engineering.tcnj.edu/wp-content ... ancing.pdf seems to suggest that the (simple) angular dimensioning should also have the degree sign repeated in the tolerance values, too. I think this is to make it distinguishable from GD&T tolerancing, where dimensional tolerances must always be in mm or inches; even for angular values (it uses the two-plane or cylinder tolerance system for angles). However, for simple dimensioning such as the one currently used in TechDraw, angular tolerances should have the same unit as the dimension.

Also, it'd be nice to get configurable per-dimension size for the tolerances, as well as an option to get plus-minus type printing for bilateral tolerances, i.e. when the upper and lower limit magnitudes are the same.

20200820_FreeCAD_TechDraw_Angular_Tolerance_02.png (127.23 KiB) Viewed 1264 times

OS: Debian GNU/Linux bullseye/sid (KDE//usr/share/xsessions/plasma)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.22270 (Git)
Build type: Unknown
Branch: master
Hash: 45d28c2367f5714cf5463b3373979c2a6f2779bf
Python version: 3.8.5
Qt version: 5.14.2
Coin version: 4.0.0
OCC version: 7.4.0
Locale: English/United States (en_US)

[vanuan]

So you expected something like this?

[vanuan]

With a configuration option to do this:

20200820_FreeCAD_TechDraw_Angular_Tolerance_01.png (31.24 KiB) Viewed 1205 times

[aapo]

So you expected something like this?

Yes, indeed. I guess the printing style depends on personal preferences, but my point is that both of the missing options are more common in the literature than the current TechDraw style, which I've actually never seen used anywhere else. In your examples, though, in the plus-minus style the tolerance should be normally printed with the same typeface size as the dimension value.

[aapo]

Also, the current TechDraw style does not bother me personally that much, because I always use bilateral angle tolerances and abuse the formatting string to include the plus-minus character and an extra degree character. There is a small error, namely the spacing before the degree character is larger for the tolerance, but this hasn't been a problem for anyone reading a drawing.

My reason for posting about this was that for a novice user the trick won't be obvious, and also it's a bit of a hack and it'd be nice to get a reasonable default style out-of-the-box.

20200820_FreeCAD_TechDraw_Angular_Tolerance_03.png (24.18 KiB) Viewed 1188 times

[wandererfan]

Currently, when putting tolerances for FreeCAD TechDraw angular dimensions, TechDraw places the tolerance values between the angle value and the degree sign, which I feel is not optimal for readibility.

Doing it this way is an easy change - just moving a few lines of code. I could squeeze it in within a day or two.

moveTolerance.png (20.14 KiB) Viewed 1166 times

Adding the unit to the tolerance text and/or adding formatting options is likely more involved and I'd have to find some time to do it.

Let me know what you think.

[chrisb]

In my book on ISO 2768 there is no unit used for linear dimensions, only for angles.

[aapo]

Doing it this way is an easy change - just moving a few lines of code. I could squeeze it in within a day or two.
moveTolerance.png

Adding the unit to the tolerance text and/or adding formatting options is likely more involved and I'd have to find some time to do it.

Let me know what you think.

I was perhaps a bit obscure in my post, I didn't mean literal units (like "mm") for distances. I meant that when one leaves the degree-character out, it already means a literal unit like "mm" or "inch". As chrisb said, one is not supposed to print out the unit; my point was that leaving the degree-character out of the small tolerance numbers strictly speaking (wrongly) implies that the tolerances are distances, not angles. But as chrisb told, no printing of "mm" or "inch" on drawings, please!

That said, I still think that your suggestion for a quick fix is an improvement over the current state of affairs. So, that gets my vote.


EDIT: IMHO, the screenshot from the dimensioning course material pdf above probably best shows the desired state of affairs. TechDraw is pretty close already, with some minor options and the degree chars in angle tolerances missing.

[wandererfan]

That said, I still think that your suggestion for a quick fix is an improvement over the current state of affairs. So, that gets my vote.

Try with this git commit cc81f791da.

[aapo]

Try with this git commit cc81f791da.

Works like a charm, muchos gracias!

You even did the "°"-characters for the small tolerance texts, so it's now perfectly standard-compliant. I also tested my preferred hack method, it also still works (the left one in the pic), as well as the default angular style is now correct (the green one). I tested linear dimensions, too, they also seem to be a-ok. So, you got everything fixed, and the default angular tolerances are now sane. Great job!

20200820_FreeCAD_TechDraw_Angular_Tolerance_04.png (76.02 KiB) Viewed 994 times

OS: Debian GNU/Linux bullseye/sid (KDE//usr/share/xsessions/plasma)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.22283 (Git)
Build type: Unknown
Branch: master
Hash: 4b7e64381c55f28b0d9e93258126c2472d168881
Python version: 3.8.5
Qt version: 5.14.2
Coin version: 4.0.0
OCC version: 7.4.0
Locale: English/United States (en_US)