Pocket - Failed to validate broken face

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kunlun121
Posts: 30
Joined: Mon Jan 24, 2022 8:24 pm

Pocket - Failed to validate broken face

Post by kunlun121 »

Hi -

I'm a FreeCAD noob and ran into a problem I can't solve. I have searched the forum and found others struggling with this problem. None of the solutions seem to work for me tho.

Here is my version info:

OS: macOS 10.16
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.24366 (Git)
Build type: Release
Python version: 3.9.7
Qt version: 5.12.9
Coin version: 4.0.0
OCC version: 7.5.3
Locale: C/Default (C)

This is the error message I'm getting:
Screenshot 2022-01-24 at 21.35.35.png
Screenshot 2022-01-24 at 21.35.35.png (34.5 KiB) Viewed 1014 times
It occurs when I try to make pockets from the sketch highlighted here:
Screenshot 2022-01-24 at 21.40.09.png
Screenshot 2022-01-24 at 21.40.09.png (360.86 KiB) Viewed 1014 times
I tried a few times. Strangely enough I managed to successfully make a pocket based on one of the two shapes. After modifying my sketch the error came up and didn't go away. Redrawing the sketch didn't help. If I draw a simple, unconstrained rectangle on the face, it's easy to make a pocket. But not with these shapes. What am I doing wrong?
Attachments
Headshell_v003.FCStd
(31.83 KiB) Downloaded 11 times
GeneFC
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Re: Pocket - Failed to validate broken face

Post by GeneFC »

Your sketch is not connected at most of the arc to line junctions.

It is necessary to connect all such points, generally with with a "coincident" or "tangent" constraint.

Merely placing the elements on top of each other does not create the connection.

The sketch validation tool from the main menu (Sketch >> Validate sketch) shows the error points.

Capture.JPG
Capture.JPG (27.17 KiB) Viewed 992 times

You have used way too many dimensional constraints in an attempt to overlay the element ends. This is not only too busy but also ineffective.

Gene
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Shalmeneser
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Re: Pocket - Failed to validate broken face

Post by Shalmeneser »

Use symmetry upon axis !
Attachments
Capture du 2022-01-24 23-17-07.png
Capture du 2022-01-24 23-17-07.png (31.89 KiB) Viewed 959 times
Headshell_SHALM.FCStd
(36.37 KiB) Downloaded 11 times
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Shalmeneser
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Re: Pocket - Failed to validate broken face

Post by Shalmeneser »

* No zero-dimension !
* No twice the same dimension !
use geometrical constraint over dimensionnal constraint.
(you need to have less job to change one dimension value.)
Attachments
Capture du 2022-01-24 23-19-50.png
Capture du 2022-01-24 23-19-50.png (28.53 KiB) Viewed 952 times
Capture du 2022-01-24 23-22-54.png
Capture du 2022-01-24 23-22-54.png (15.9 KiB) Viewed 952 times
kunlun121
Posts: 30
Joined: Mon Jan 24, 2022 8:24 pm

Re: Pocket - Failed to validate broken face

Post by kunlun121 »

Shalmeneser wrote: Mon Jan 24, 2022 10:24 pm * No zero-dimension !
* No twice the same dimension !
use geometrical constraint over dimensionnal constraint.
(you need to have less job to change one dimension value.)
Thank you for this guidance - GeneFC too, I take it you're saying the same thing. Also the symmetry upon axis is nice to know. I had been missing that but it greatly improves the workflow.

It worked like a charm:
Screenshot 2022-01-25 at 09.44.34.png
Screenshot 2022-01-25 at 09.44.34.png (476.19 KiB) Viewed 851 times
Now my next hurdle: I'd like to make the corners of the pocket rounded. As if an ice cream scoop scooped it out of the metal, something like the front block in this image:
what-is-profile-milling-2.jpg
what-is-profile-milling-2.jpg (17.88 KiB) Viewed 851 times
How can I make FreeCAD do this?
chrisb
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Re: Pocket - Failed to validate broken face

Post by chrisb »

You can use Fillets. But you should know that these may have to be redone, if you later on make changes to previous steps; see the topological naming problem for details.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
kunlun121
Posts: 30
Joined: Mon Jan 24, 2022 8:24 pm

Re: Pocket - Failed to validate broken face

Post by kunlun121 »

chrisb wrote: Tue Jan 25, 2022 8:58 am You can use Fillets. But you should know that these may have to be redone, if you later on make changes to previous steps; see the topological naming problem for details.
Thank you Chris. I had tried fillets, but keep getting this notification:
Screenshot 2022-01-25 at 10.10.23.png
Screenshot 2022-01-25 at 10.10.23.png (39.68 KiB) Viewed 819 times
My problem is either that I don't know what face or edge to apply the fillet to (tried many), or that my model has one or more other mistakes in it. Would you have any idea what I can try to get those nice round edges?
Attachments
Headshell_v003.FCStd
(42.64 KiB) Downloaded 8 times
kunlun121
Posts: 30
Joined: Mon Jan 24, 2022 8:24 pm

Re: Pocket - Failed to validate broken face

Post by kunlun121 »

Thanks for the heads up about having to redo them after subsequent changes. I'm not worried about that for this model, as likely this is the last change I'll make to it before sending it off for production.
chrisb
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Re: Pocket - Failed to validate broken face

Post by chrisb »

The fillet must not consume all of the adjacent face. Thus a radius of 0.499 works, 0.5 fails.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
kunlun121
Posts: 30
Joined: Mon Jan 24, 2022 8:24 pm

Re: Pocket - Failed to validate broken face

Post by kunlun121 »

Perfect, done.
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