Sketcher solver issue

[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?

[Shalmeneser]

...

Which sketch ?
remove : 15 then 28 then 33 --or-- 33 then 28 then 15 ?

[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)

[chrisb]

...

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.

[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.

[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]

So it is indeed the same issue as 4284.

[openBrain]

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.

[thomas-neemann]

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 (43.55 KiB) Viewed 1149 times

[thomas-neemann]

apparently this measure is missing?

1.png (8.99 KiB) Viewed 1114 times

hiddenOverconstraint-ok.FCStd

(6.97 KiB) Downloaded 15 times

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