Unwanted rounding of dimensions
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- Posts: 9
- Joined: Mon Jun 21, 2021 1:21 pm
Unwanted rounding of dimensions
I'm a fairly new user, falling at the very first hurdle in the arch workbench. I cannot create a rectangle with the desired dimensions:
File, new, select arch workbench.
Select Top plane, using the orientation tool in top RH corner of workspace.
Create rectangle.
In properties, set position to [0 0 0]
In properties, set Height = 2435 mm and Length = 2725 mm.
The problem is that FreeCad changes these values to 2440.00 and 2730.00 mm respectively.
What am I doing wrong? (Apologies if this is a FAQ - I have searched for a long while, honest!)
I think I've eliminated snap-to-grid as a cause, but I might be wrong. Working plane is set to "auto".
OS: Ubuntu 18.04.5 LTS (KDE/plasma)
Word size of FreeCAD: 64-bit
Version: 0.20.
Build type: Release
Branch: unknown
Hash: 90735172918871eb9b19d6831a9a139775b7122f
Python version: 3.6.9
Qt version: 5.9.5
Coin version: 4.0.0a
OCC version: 7.5.1
Locale: English/UnitedKingdom (en_GB)
File, new, select arch workbench.
Select Top plane, using the orientation tool in top RH corner of workspace.
Create rectangle.
In properties, set position to [0 0 0]
In properties, set Height = 2435 mm and Length = 2725 mm.
The problem is that FreeCad changes these values to 2440.00 and 2730.00 mm respectively.
What am I doing wrong? (Apologies if this is a FAQ - I have searched for a long while, honest!)
I think I've eliminated snap-to-grid as a cause, but I might be wrong. Working plane is set to "auto".
OS: Ubuntu 18.04.5 LTS (KDE/plasma)
Word size of FreeCAD: 64-bit
Version: 0.20.
Build type: Release
Branch: unknown
Hash: 90735172918871eb9b19d6831a9a139775b7122f
Python version: 3.6.9
Qt version: 5.9.5
Coin version: 4.0.0a
OCC version: 7.5.1
Locale: English/UnitedKingdom (en_GB)
Re: Unwanted rounding of dimensions
Hi, Welcome,
Have a look at your 'Unit' preferences : https://wiki.freecadweb.org/Preferences_Editor#Units
Have a look at your 'Unit' preferences : https://wiki.freecadweb.org/Preferences_Editor#Units
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- Posts: 9
- Joined: Mon Jun 21, 2021 1:21 pm
Re: Unwanted rounding of dimensions
Unit preferences are:
Unit system: Standard (mm/s/kg/degree)
Number of decimals: 2
Minimum fractional inch: 1/2" (greyed out)
Unit system: Standard (mm/s/kg/degree)
Number of decimals: 2
Minimum fractional inch: 1/2" (greyed out)
Re: Unwanted rounding of dimensions
I think you have to increase 'Number of decimals' because internally FreeCAD applies this to meters as your numbers are greater than 1000 mm.GrahamKing wrote: ↑Mon Jun 21, 2021 2:52 pm Unit preferences are:
Unit system: Standard (mm/s/kg/degree)
Number of decimals: 2
Minimum fractional inch: 1/2" (greyed out)
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- Posts: 9
- Joined: Mon Jun 21, 2021 1:21 pm
Re: Unwanted rounding of dimensions
Thank you openBrain, that did the trick!
But how extremely counter-intuitive! The UI now shows 4 decimal places (2435.0000) as opposed to the previous 2 (2440.00), but what has really changed is the number of significant figures rather than the spurious decimal places. And the number of sig.fig. depends on the magnitude of the number, rather than the precision of the computer's arithmetic?? I see I shall have to be very careful indeed with this piece of software.
But how extremely counter-intuitive! The UI now shows 4 decimal places (2435.0000) as opposed to the previous 2 (2440.00), but what has really changed is the number of significant figures rather than the spurious decimal places. And the number of sig.fig. depends on the magnitude of the number, rather than the precision of the computer's arithmetic?? I see I shall have to be very careful indeed with this piece of software.
Re: Unwanted rounding of dimensions
Actually what I'm surprised is that numbers are displayed in mm...GrahamKing wrote: ↑Mon Jun 21, 2021 3:10 pm But how extremely counter-intuitive! The UI now shows 4 decimal places (2435.0000) as opposed to the previous 2 (2440.00), but what has really changed is the number of significant figures rather than the spurious decimal places. And the number of sig.fig. depends on the magnitude of the number, rather than the precision of the computer's arithmetic?? I see I shall have to be very careful indeed with this piece of software.
Could you attach the file (or a minimal part) to show this ?
Re: Unwanted rounding of dimensions
Yeah, it's counterintuitive in other direction as well:
https://forum.freecadweb.org/viewtopic.php?f=3&t=52057
Perhaps "my" setting will work for you as well?
I was equally surprised with FreeCAD logic
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- Posts: 9
- Joined: Mon Jun 21, 2021 1:21 pm
Re: Unwanted rounding of dimensions
Gladly.
Screenshot:
The FC file:
Screenshot:
The FC file:
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- Posts: 9
- Joined: Mon Jun 21, 2021 1:21 pm
Re: Unwanted rounding of dimensions
... and while folks are digesting that, I'd like to say thank you for the very rapid and helpful response. Meanwhile I'll let my bricklayer know that he doesn't need to bring his laser interferometer
Re: Unwanted rounding of dimensions
This sort of issue came up a couple of years ago. I don't have any references, but I recall that the behavior was workbench-dependent. The OP says he was using Arch WB.
I would have expected that all such considerations were built into the base application, but that may not be correct.
Gene