Help with my fillet problem

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Vensent
Posts: 7
Joined: Sun Jan 23, 2022 2:26 pm

Help with my fillet problem

Post by Vensent »

I am new to FreeCad. And I find that it is quite sticky with the fillet function.
Anyone help me with the hole fillet?
Here is my FCStd file: https://drive.google.com/file/d/1FNLx5Q ... sp=sharing

Freecad version:
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
Attachments
20220123223344.png
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uwestoehr
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Re: Help with my fillet problem

Post by uwestoehr »

I see that you selected 4 edges. But you only want a single edge to be filleted. Therefore only select this single edge.
chrisb
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Re: Help with my fillet problem

Post by chrisb »

The problem here seems to be a different one, probably a precision issue:
In Pocket001 the hole you try to fillet is a perfect circle. Alas, when you mirror it, you get a tiny deviation and you now the border is made from two half circles. Fillet fails frequently on near-180° angles, and does so probably here.

Solution (guess):
- remove the circle from Sketch001
- add another pocket after the mirror with just that circle.

Besides: Don't use Multitransform if you want to make only a mirror. Use the mirror itself.
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uwestoehr
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Re: Help with my fillet problem

Post by uwestoehr »

I had a look at your file and I don't understand why the filleting fails. The only way I got it to work is to make the fillet directly after the pocket.

Here is your file where I did this (Fillet006):
fillet_failed.FCStd
(600.93 KiB) Downloaded 12 times

hints:
* you can also select faces when you want all their edges to be filleted. i did this with some of your pockets as demonstration.
* when you have e.g. a 4.5 mm thick sheet, don't apply 2 fillets with each 2.25 mm because they would connect each other at zero. When there is just a little precision issue during the calculation, the filleting would fail because the outcome might not be zero but e.g. -0.0000001
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uwestoehr
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Re: Help with my fillet problem

Post by uwestoehr »

chrisb wrote: Sun Jan 23, 2022 5:18 pm The problem here seems to be a different one, probably a precision issue:
In Pocket001 the hole you try to fillet is a perfect circle. Alas, when you mirror it, you get a tiny deviation and you now the border is made from two half circles. Fillet fails frequently on near-180° angles, and does so probably here.
Thanks! Yes, this is the reason.
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Shalmeneser
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Re: Help with my fillet problem

Post by Shalmeneser »

Other way to do your piece (only PartDesign).
Attachments
fillet_failed_SHALM.FCStd
(353.11 KiB) Downloaded 15 times
Capture d’écran 2022-01-23 192828.png
Capture d’écran 2022-01-23 192828.png (55.65 KiB) Viewed 1327 times
Vensent
Posts: 7
Joined: Sun Jan 23, 2022 2:26 pm

Re: Help with my fillet problem

Post by Vensent »

chrisb wrote: Sun Jan 23, 2022 5:18 pm The problem here seems to be a different one, probably a precision issue:
In Pocket001 the hole you try to fillet is a perfect circle. Alas, when you mirror it, you get a tiny deviation and you now the border is made from two half circles. Fillet fails frequently on near-180° angles, and does so probably here.

Solution (guess):
- remove the circle from Sketch001
- add another pocket after the mirror with just that circle.

Besides: Don't use Multitransform if you want to make only a mirror. Use the mirror itself.
Thanks very much, I now get to know why it failed.
kisolre
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Re: Help with my fillet problem

Post by kisolre »

I hate to be "that guy" but setting Refine=true again shows its horns...

Refine is not just a visual prettifying operations. It is computationally intensive and prone to errors. Here the refine of MultiTransform001 (two overlapping cylindrical surfaces) fails to properly identify the border circle edges as one (they might look like arcs but could be splines in reality) and this causes errors in later operations. I noticed several fails like that one with cylindrical surfaces.

Without the Mesh object file is 864k - small enough for direct forum attachment.
Vensent
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Joined: Sun Jan 23, 2022 2:26 pm

Re: Help with my fillet problem

Post by Vensent »

Shalmeneser wrote: Sun Jan 23, 2022 6:27 pm Other way to do your piece (only PartDesign).
Thanks, Shalmeneser.
Your work is much more simple and elegant. I will adopt your work to 3D print.
Vensent
Posts: 7
Joined: Sun Jan 23, 2022 2:26 pm

Re: Help with my fillet problem

Post by Vensent »

uwestoehr wrote: Sun Jan 23, 2022 5:19 pm I had a look at your file and I don't understand why the filleting fails. The only way I got it to work is to make the fillet directly after the pocket.

Here is your file where I did this (Fillet006):
fillet_failed.FCStd


hints:
* you can also select faces when you want all their edges to be filleted. i did this with some of your pockets as demonstration.
* when you have e.g. a 4.5 mm thick sheet, don't apply 2 fillets with each 2.25 mm because they would connect each other at zero. When there is just a little precision issue during the calculation, the filleting would fail because the outcome might not be zero but e.g. -0.0000001
Thanks. And I'm wondering how the Fillet006 you made can be inserted to the middle of the Part-Design? I can just make a new fillet to end of the Part-Design.
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