trouble with fillets

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toot-toot
Posts: 7
Joined: Thu Aug 06, 2020 8:43 pm

trouble with fillets

Post by toot-toot »

Okay, -totally new user. I thought this would be easy after 15 years experience with PTC Creo and its predecessors but it has been painful. I must have 20+ hours in 3 or 4 attempts to create this part. So, my latest problem is that, after creating fillets around the inside intersections of the web with the bosses by selecting the 12 edges, I can't do the same on the outside wall. I can do a few, selecting edges individually or in pairs but then it gives me "failed to construct fillet" or something to that effect and the whole pad disappears or appears with a sideways cut in the boss I was attempting to fillet. All the tutorial videos I find for fillets only demonstrate on a simple block model so they are of no help. What am I doing wrong?
Ultimately, I am going to draft this puppy and I already read that I should have drafted first so I will go back and do that but in the meantime I need to figure the fillet thing out before I invest more time in the part. I will attempt to attach the file.
chrisb
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Re: trouble with fillets

Post by chrisb »

With all these construction circles you probably had some partially redundant constraints of which parts got silently removed, I didn't nail it down. Instead I constrained it in a way I would do it, and then the fillets work.

If you are interested in finding the error, you can remove the constraints one by one and verify after each deletion that the numboer of degrees of freedom rises in the expected way:
Coincidence 2
Equality 1
Point-on-object 1
Diameter 1.
Attachments
attemp3_cb.FCStd
(139.45 KiB) Downloaded 13 times
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
GeneFC
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Re: trouble with fillets

Post by GeneFC »

For some reason your sketch is slightly broken. I have not figured out just what is wrong, but the pad created from the sketch is invalid. One of the external bosses does not have a wall. To check the pad switch to the Part WB and select "Check Geometry" from the Part menu.

I took out all the construction geometry (most of which I do not understand), and then the sketch, pad, and fillets worked correctly.

Fillets are one of the weak areas in FreeCAD. In this case the best thing would be to make the fillets in the sketch. Of course you probably plan to continue with a more complex model, so working in the sketch may not be possible.

Gene
chrisb
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Re: trouble with fillets

Post by chrisb »

I was on the wrong track - and Gene probably too: If you do a full recompute the missing wall appears and I can create all other fillets in one go.
Nevertheless I think that the sketching should be improved.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
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papyblaise
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Re: trouble with fillets

Post by papyblaise »

Select all edges in one and done
Attachments
filets.PNG
filets.PNG (75.19 KiB) Viewed 381 times
GeneFC
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Re: trouble with fillets

Post by GeneFC »

chrisb wrote: Fri Aug 07, 2020 12:18 am I was on the wrong track - and Gene probably too
:oops: :oops: :oops: :oops: :oops:

I almost always do a recompute as a first step in troubleshooting. I guess it was late.

In any case, this is what I saw.

As loaded.PNG
As loaded.PNG (16.13 KiB) Viewed 340 times
Check geometry.PNG
Check geometry.PNG (5.53 KiB) Viewed 340 times
After recompute.PNG
After recompute.PNG (14.94 KiB) Viewed 340 times

Gene
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