Arc constrain on rectangle corners disappears after applying symmetrical constrain

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r2aon
Posts: 3
Joined: Thu Mar 23, 2023 7:39 am

Arc constrain on rectangle corners disappears after applying symmetrical constrain

Post by r2aon »

Hello there! I'm new to 3d modeling and use FreeCAD only for week or so since i got my first 3d printer. With the help of FreeCAD i managed to make about ten useful parts for my projects while learning how to use it form YT tutorials and mostly FreeCAD wiki, but now i kinda stuck with it.

I'm trying to make rectangular shape in sketcher with rounded corners. Here is workflow:

1) Make rectangle of any shape and dimensions with "Create rectangles" tool, it additionally adds vertical and horizontal constrains to lines
2) Round all four corners with "Fillets" tool
3) Constrain rounded corners with same 2mm radius with "Constrain arc or circle" tool (result in pic. 1)
3) Add symmetrical constrain between two points of opposing lines and axis between them (pic. 2)

And after adding symmetrical constrain something happens that I can't understand: constrain added and working like i expect it, but one of the four fillet radius constrains disappears (pic. 3). It still indeed 2mm radius, but when i try to reapply radius constrain it shows in dialog window that radius is still 2mm (pic. 5) but when hitting "OK" error message pops up (pic. 6).
It all constrained and i can continue sketching, but it makes me think i'm doing something wrong way. Help me pls) Thanks in advance!
Screenshots of process:
Image Image Image Image Image Image

Added attachment with whole project, problematic corners in Sketch005

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: Russian/Russia (ru_RU)
Attachments
Magnetic viewer compact rectangle.FCStd
trouble corners in Sketch005
(104.37 KiB) Downloaded 7 times
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papyblaise
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Joined: Thu Jun 13, 2019 4:28 pm
Location: France

Re: Arc constrain on rectangle corners disappears after applying symmetrical constrain

Post by papyblaise »

it is fortunate that there is a little intelligence in this world of raw!
the "removal of redundancy" function works: when you make the symmetry one of the 2mm radius is redundant so it removes it, it's perfect
note that there is in the rectangle creation drop-down menu a tool that makes a rectangle with equal rounded corners
note2: you can do a diagonal centering to have the rectangle in the center in one go
r2aon
Posts: 3
Joined: Thu Mar 23, 2023 7:39 am

Re: Arc constrain on rectangle corners disappears after applying symmetrical constrain

Post by r2aon »

Thanks a lot, now i get it, "problem" solved)
Also huge thanks for notes, from now on i will pay more attention to drop-down menus and try to use right tools for a job)
chrisb
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Re: Arc constrain on rectangle corners disappears after applying symmetrical constrain

Post by chrisb »

r2aon wrote: Thu Mar 23, 2023 8:13 am Here is workflow:
Concerning your modeling:
A few remarks on helping the helpers:
- when presenting a problem, it is always helpful to have a minimal example showing the issue
- when you really have to show a file with several bodies and lots of sketches, don't leave it to the helpers to find the one you are talking

Concerning your modeling: When the geometry requires things such as fillets to be equal, then make them equal instead of repeating the dimensions.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
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Shalmeneser
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Location: Fr

Re: Arc constrain on rectangle corners disappears after applying symmetrical constrain

Post by Shalmeneser »

:lol: You just need ONE dimension an not 28.
Attachments
Capture d’écran 2023-03-23 125121.jpg
Capture d’écran 2023-03-23 125121.jpg (119.39 KiB) Viewed 335 times
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Shalmeneser
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Re: Arc constrain on rectangle corners disappears after applying symmetrical constrain

Post by Shalmeneser »

:idea:
Attachments
Magnetic viewer compact rectangle_SHALM.FCStd
(117.52 KiB) Downloaded 5 times
Capture d’écran 2023-03-23 132505.jpg
Capture d’écran 2023-03-23 132505.jpg (84.04 KiB) Viewed 312 times
Capture d’écran 2023-03-23 132546.jpg
Capture d’écran 2023-03-23 132546.jpg (16.14 KiB) Viewed 312 times
r2aon
Posts: 3
Joined: Thu Mar 23, 2023 7:39 am

Re: Arc constrain on rectangle corners disappears after applying symmetrical constrain

Post by r2aon »

chrisb and Shalmeneser thank you so much guys, appreciate time you spent to even show how to do it proper and faster way, haven't used MultiTransform yet, i will definitely try it in next projects. I made those four corner stops by mirroring in sketch, but to my sadness constraints didn't mirror so i had to manually set them while trying not to move something, now it looks funny even to me)
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