Sketcher solver issue

Post here for help on using FreeCAD's graphical user interface (GUI).
Forum rules
and Helpful information
IMPORTANT: Please click here and read this first, before asking for help

Also, be nice to others! Read the FreeCAD code of conduct!
chrisb
Veteran
Posts: 51227
Joined: Tue Mar 17, 2015 9:14 am

Sketcher solver issue

Post by chrisb »

I have the attached Sketch derived from another forum post. It is fully constrained and seems to be ok. However, if I remove constraints 15, 28, 33 it becomes overconstraint.

Seems to be related to issue #4284, yet it is different. Can you please verify. In case you can do so, is it a new ticket?
Attachments
hiddenOverconstraint.FCStd
(5.83 KiB) Downloaded 20 times
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
User avatar
Shalmeneser
Veteran
Posts: 8220
Joined: Wed Dec 23, 2020 12:04 am
Location: Fr

Re: Sketcher solver issue

Post by Shalmeneser »

chrisb wrote: Wed Dec 15, 2021 7:42 pm ...
Which sketch ?
remove : 15 then 28 then 33 --or-- 33 then 28 then 15 ?
User avatar
adrianinsaval
Veteran
Posts: 5369
Joined: Thu Apr 05, 2018 5:15 pm

Re: Sketcher solver issue

Post by adrianinsaval »

problem seems to be with constraint 28 removing the other 2 was not necessary but it also happened if I removed them, even when it's shown as over constrained I could move the sketch and when releasing the mouse it would show as under constrained

Code: Select all

OS: Manjaro Linux (KDE/plasma)
Word size of FreeCAD: 64-bit
Version: 0.20.26620 (Git) AppImage
Build type: Release
Branch: (HEAD detached at 813e2cc)
Hash: 813e2cc66e0a5d3dc6ff203adceff3ddd65b4288
Python version: 3.9.7
Qt version: 5.12.9
Coin version: 4.0.0
OCC version: 7.5.3
Locale: English/United Kingdom (en_GB)
Attachments
sketch.gif
sketch.gif (476.49 KiB) Viewed 1325 times
chrisb
Veteran
Posts: 51227
Joined: Tue Mar 17, 2015 9:14 am

Re: Sketcher solver issue

Post by chrisb »

Shalmeneser wrote: Wed Dec 15, 2021 8:07 pm
chrisb wrote: Wed Dec 15, 2021 7:42 pm ...
Which sketch ?
remove : 15 then 28 then 33 --or-- 33 then 28 then 15 ?
Sorry, uploaded wrong file. It may take a while, I probably didn't save.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
chrisb
Veteran
Posts: 51227
Joined: Tue Mar 17, 2015 9:14 am

Re: Sketcher solver issue

Post by chrisb »

I updated the file above. I had meant to remove all three at once - or from higher to lower.

It is indeed sufficient to remove Constraint28 to show the issue.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
User avatar
Willem
Veteran
Posts: 1826
Joined: Fri Aug 12, 2016 3:27 pm
Location: Lisse, The Netherlands

Re: Sketcher solver issue

Post by Willem »

The problem is that equality constraints 29 and 32 are the same. One of them is redundant and the solver missed that this constraint exist 2 times.
chrisb
Veteran
Posts: 51227
Joined: Tue Mar 17, 2015 9:14 am

Re: Sketcher solver issue

Post by chrisb »

So it is indeed the same issue as 4284.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
openBrain
Veteran
Posts: 8997
Joined: Fri Nov 09, 2018 5:38 pm
Contact:

Re: Sketcher solver issue

Post by openBrain »

chrisb wrote: Thu Dec 16, 2021 10:48 am So it is indeed the same issue as 4284.
When I open the file of this bug with latest 0.20, it indicates that sketch has partially redundant constraints (just as it is in the file).
I'm afraid maybe solver has actually no real issue but the sketch is badly constrained by some way. Will try to investigate later.
User avatar
thomas-neemann
Veteran
Posts: 9978
Joined: Wed Jan 22, 2020 6:03 pm
Location: Osnabrück DE

Re: Sketcher solver issue

Post by thomas-neemann »

chrisb wrote: Wed Dec 15, 2021 7:42 pm
if you mirror the sketch, such an effect also occurs. does that help isolate the error?



hiddenOverconstraint-gespiegelt.FCStd
(8.31 KiB) Downloaded 14 times



Bildschirmfoto_2021-12-16_12-47-42.png
Bildschirmfoto_2021-12-16_12-47-42.png (43.55 KiB) Viewed 1149 times
Gruß Dipl.-Ing. (FH) Thomas Neemann

https://www.youtube.com/@thomasneemann5 ... ry=freecad
User avatar
thomas-neemann
Veteran
Posts: 9978
Joined: Wed Jan 22, 2020 6:03 pm
Location: Osnabrück DE

Re: Sketcher solver issue

Post by thomas-neemann »

chrisb wrote: Wed Dec 15, 2021 7:42 pm
apparently this measure is missing?

1.png
1.png (8.99 KiB) Viewed 1114 times
hiddenOverconstraint-ok.FCStd
(6.97 KiB) Downloaded 15 times

https://www.youtube.com/watch?v=m0jQzHCJWDY

phpBB [video]
Gruß Dipl.-Ing. (FH) Thomas Neemann

https://www.youtube.com/@thomasneemann5 ... ry=freecad
Post Reply