Under-constrained sketch with 1 degree of freedom-Newbie

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sujitth
Posts: 1
Joined: Thu Jan 27, 2022 12:44 pm

Under-constrained sketch with 1 degree of freedom-Newbie

Post by sujitth »

Hi,

I just started learning FreeCAD by following Flowwie's video tutorial.
and facing an issue on the Pacman exercise using sketch method.(https://youtu.be/u8otDF_C_fw?t=1395)

am always getting an error called "Under-constrained sketch with 1 degree of freedom", I have tried to re-do it and made sure all lines are at the desired positions, but same error.

Please find my FreeCAD version details:
OS: Windows 10 Version 2009
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.24267 +99 (Git)
Build type: Release
Branch: Branch_0.19.3
Hash: 6530e364184ce05ccff39501e175cf2237e6ee4b
Python version: 3.8.6+
Qt version: 5.15.2
Coin version: 4.0.1
OCC version: 7.5.3
Locale: English/United States (en_US)

I have attached the file I created for reference, kindly let me know what is the mistakes I have done.

and one more thing is that I find a bit difficult to start the lines/circles at origin 0.00,0.00 point exactly with mouse, how it has been doing by the other Freecad users?

and I noticed Mr Flowwie was easily doing it on the video(but it was like 0.7,0.1 and 0.2,-0.1, is there somekind of auto-snap or something enabled for him?)
Attachments
Pacman.FCStd
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drmacro
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Joined: Sun Mar 02, 2014 4:35 pm

Re: Under-constrained sketch with 1 degree of freedom-Newbie

Post by drmacro »

As for your question about 0,0 and constraining. Draw the line with out regard to getting the vertex on the Root point. Then select the vertex of the line and use the Select Origin Image , then click constrain point on pointImage

If you deactivate Constraint4 you find the line is not constrained in length because its vertex is constrained to the vertical axis, but the the end vertex of the arc.
Snip macro screenshot-b69077.png
Snip macro screenshot-b69077.png (172.14 KiB) Viewed 652 times
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Shalmeneser
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Location: Fr

Re: Under-constrained sketch with 1 degree of freedom-Newbie

Post by Shalmeneser »

When looking for under-constrained sketch :
* try to move anything
* select point (box from left to right) then Sketcher_ConstrainCoincident (shortcut 'C').
* count the number of line in Task window to look for double line.
TheMarkster
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Joined: Thu Apr 05, 2018 1:53 am

Re: Under-constrained sketch with 1 degree of freedom-Newbie

Post by TheMarkster »

Change the radius to 75 and watch what happens.
chrisb
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Joined: Tue Mar 17, 2015 9:14 am

Re: Under-constrained sketch with 1 degree of freedom-Newbie

Post by chrisb »

Using 0.20 can be recommended for this: If parts of your sketch are already fully constrained, they are shown in a different color.
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