[discarded] User accessible settings for modelling precision

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Ulicad
Posts: 311
Joined: Tue Aug 16, 2022 10:35 am
Location: de_DE

[discarded] User accessible settings for modelling precision

Post by Ulicad »

Edit Dec. 2023:
The idea behind the topic - getting sufficient certainty on the subject for myself and other new users alike - could not be gained.
For this reason it is discarded.


Remark:
This subject is rather complex.
For someone liking to enter more deeply into the matter, please see Fillet on cylinder edge bumpy for instance.


For the quick passer by, stripped down to the titles meaning, the accuracy may be set by the user in the following locations:

1) Preferences -> General -> Units -> Number of decimals

2) Preferences -> Part Design -> Shape View -> Tesselation
  • Maximum deviation ..
  • Maximum angular ..
'Expert settings' may be used in the Sketcher.

3) WB Sketcher: (Combo view) -> Tasks -> Advanced solver control

Installation info:

Code: Select all

OS: Windows 10 Version 2009
Word size of FreeCAD: 64-bit
Version: 0.20.1.29410 (Git)
Build type: Release
Branch: releases/FreeCAD-0-20
Hash: f5d13554ecc7a456fb6e970568ae5c74ba727563
Python 3.8.10, Qt 5.15.2, Coin 4.0.1, Vtk 8.2.0, OCC 7.6.3
Locale: German/Germany (de_DE)

edit:
Due to a mishap, the original post-text was deleted and could not be restored.
Most of it, if not all, now was found again and it is reentered here again to avoid confusion.
The original text itself has been striked through competely.


(Technical terms and language are creating some obstacles, please forgive..)

As a user of FC, I definitely like to be in control of the precision, by which my CAD-model is calculated by FC (irrespective of the view presented by whichever SW). There are cases, I even need to control them due to various reasons and requirements (not to be listed here actually). 'Fine' modelling needs processing time, understood.

What I could find until now was:

Preferences -> General -> Units -> Number of decimals:
It appears as if the no. of decimal places used for computation here would not be influenced by the user. If this is true, it would not matter for the modelling precision. Otherwise, is would be neccessary for the control of the processing precision.

Preferences -> Part Design -> Shape View -> Tesselation:
Maximum deviation depending... (rest not fully understood) allows a degree setting. To what I understood by now, this IS influencing the coarseness of curved surfaces of a models shape.
Last edited by Ulicad on Sun Dec 03, 2023 7:28 am, edited 5 times in total.
Regards, Ulicad / Uli
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Roy_043
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Re: Only partial "Shape View" settings?

Post by Roy_043 »

"Another thread"... Why not give us a link? But my guess is the screenshot is from RT's link branch.
chrisb
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Re: Only partial "Shape View" settings?

Post by chrisb »

Ulicad wrote: Tue Mar 21, 2023 7:32 am In FC, (some?) important settings for the internal precision, one may find in a Tab labeled "Shape View" (in Part Design).
Though a bit off topic, it should be noted, that these settings are not controlling the internal precision, but rather the external. These values are used for the visual representation, but not for the internal calculations (except some border cases, where the bounding box is used).
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
Ulicad
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Location: de_DE

Re: Only partial "Shape View" settings?

Post by Ulicad »

Roy_043 wrote: Tue Mar 21, 2023 8:45 am "Another thread"... Why not give us a link? But my guess is the screenshot is from RT's link branch.
Thank you for replying.

Hmm - if "another thread" for this IMHO general and isolated case is not according to the nettiquette, please let me know. It can be included elswhere of course.

Sadly, I already forgot from where the screenshot was - would it matter?

Was thinking already about a dedicated topic about Global and WB-related precision settings (overwriting the global ones), if existing). Thought this could help others too (if it is well done of course...). This topic here could somewhat later be edited for that purpose, including the title, as soon as I find the time - or deleted, whatever deems fit.
Regards, Ulicad / Uli
---
en: New FC-user, virgin to previous CAD-work, labouring on his new hobby Ulis Blog
de: Neuer FC-Nutzer, ohne vorhergehende CAD-Erfahrung, beschäftigt mit seinem neuen Hobby Ulis Blog
Ulicad
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Location: de_DE

Re: Only partial "Shape View" settings?

Post by Ulicad »

chrisb wrote: Tue Mar 21, 2023 9:43 am
Ulicad wrote: Tue Mar 21, 2023 7:32 am In FC, (some?) important settings for the internal precision, one may find in a Tab labeled "Shape View" (in Part Design).
Though a bit off topic, it should be noted, that these settings are not controlling the internal precision, but rather the external. These values are used for the visual representation, but not for the internal calculations.
Thanks! Where may the settings for the internal precision be made? It is these, I am searching for.
Regards, Ulicad / Uli
---
en: New FC-user, virgin to previous CAD-work, labouring on his new hobby Ulis Blog
de: Neuer FC-Nutzer, ohne vorhergehende CAD-Erfahrung, beschäftigt mit seinem neuen Hobby Ulis Blog
drmacro
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Re: Only partial "Shape View" settings?

Post by drmacro »

Ulicad wrote: Tue Mar 21, 2023 9:53 am
chrisb wrote: Tue Mar 21, 2023 9:43 am
Ulicad wrote: Tue Mar 21, 2023 7:32 am In FC, (some?) important settings for the internal precision, one may find in a Tab labeled "Shape View" (in Part Design).
Though a bit off topic, it should be noted, that these settings are not controlling the internal precision, but rather the external. These values are used for the visual representation, but not for the internal calculations.
Thanks! Where may the settings for the internal precision be made? It is these, I am searching for.
Do you mean the number of decimal places you can see or type in a field.

Or the number of facets seen on a circle?
Star Trek II: The Wrath of Khan: Spock: "...His pattern indicates two-dimensional thinking."
Ulicad
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Location: de_DE

Re: Only partial "Shape View" settings?

Post by Ulicad »

At this moment I am only interested in internal precision, not what is visible to the user on the screen. Decimal places, tesselation and more?
Regards, Ulicad / Uli
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Roy_043
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Re: Only partial "Shape View" settings?

Post by Roy_043 »

Ulicad wrote: Tue Mar 21, 2023 9:51 am would it matter?
Yes, It would save us from having to search and/or guess.
drmacro
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Re: Only partial "Shape View" settings?

Post by drmacro »

Ulicad wrote: Tue Mar 21, 2023 9:59 am At this moment I am only interested in internal precision, not what is visible to the user on the screen. Decimal places, tesselation and more?
The number of decimal places see/entered is set in the Units tab of the General section in Preferences.

Tesselation is in the Part Design preferences Shape view tab.

The "internal" precision is, AFAIK, not adjustable by the user and is just that of floating point math of the compiler.
Star Trek II: The Wrath of Khan: Spock: "...His pattern indicates two-dimensional thinking."
chrisb
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Re: User accessible settings of modelling precision?

Post by chrisb »

There is one place where you can adjust the internal precision: The sketcher solves its huge equation system not algebraically, but numerically, and using the expert settings you can control this iteration process.

Please tell us, why you are interested in this. I am not aware of a mechanical production process where precision in the nanometer range would matter, perhaps an optical one?
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
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