Fillet Issues - Links go out of allowed scope

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ConnorMoran
Posts: 6
Joined: Wed Jul 17, 2019 11:23 am

Fillet Issues - Links go out of allowed scope

Postby ConnorMoran » Wed Jul 17, 2019 11:55 am

I can't for the life of me figure this out and I've looked up many posts about the same issue and still can't solve it, so sorry if the answer seems obvious. I'm not an experienced user of FreeCAD by any means.

I'm trying to fillet the edge of this computer fan I've been making, based off another design. Most fillets work but this one seems difficult.
I understand I should really be using PartDesign's fillet function but I want to use a variable fillet.

As you can see in the pictures I have the fan and I've highlighted the edges I want to fillet. It works but the faces start to get wonky.
My goal is to do this for all 4 sides but it won't have any of it. I can do about 1.5 sides before it breaks entirely.

Can anyone help?

Code: Select all

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.13541 (Git)
Build type: Release
Branch: releases/FreeCAD-0-17
Hash: 9948ee4f1570df9216862a79705afb367b2c6ffb
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: English/UnitedKingdom (en_GB)
Attachments
Fan Issue 1.png
Fan Model
Fan Issue 1.png (167.13 KiB) Viewed 198 times
Fan Issue 2.png
Edges to have fillet
Fan Issue 2.png (166.54 KiB) Viewed 198 times
Fan Issue 3.png
Screwy face
Fan Issue 3.png (168.05 KiB) Viewed 198 times
Fan Issue 4.png
Goal, and another screwy face
Fan Issue 4.png (172.32 KiB) Viewed 198 times
Computer Fan.FCStd
(427.67 KiB) Downloaded 8 times
openBrain
Posts: 2372
Joined: Fri Nov 09, 2018 5:38 pm

Re: Fillet Issues - Links go out of allowed scope

Postby openBrain » Wed Jul 17, 2019 2:49 pm

The "out of scope" comes from fact that fillet (the one of Part WB) shall be applied on Body itself and not on one of its internal operation (namely Pocket008 in your case).
A good way to achieve this is to change the Display Mode of the Body to Tip (instead of Through). That will ensure that only the Body shape is exposed and not its internal operations.
ConnorMoran
Posts: 6
Joined: Wed Jul 17, 2019 11:23 am

Re: Fillet Issues - Links go out of allowed scope

Postby ConnorMoran » Wed Jul 17, 2019 4:30 pm

Thanks, I did what you said but it's still screwing up it seems.
The entire main face disappears if I do this bottom left vertex of this face, and this top left vertex I've posted pictures of refuses to fillet.
I don't know why, I got no errors this time.
Attachments
Fan Issue 5.png
Funky face
Fan Issue 5.png (159.87 KiB) Viewed 170 times
Fan Issue 6.png
Offending top left vertex
Fan Issue 6.png (139.32 KiB) Viewed 170 times
Fan Issue 7.png
Showing I selected tip display mode
Fan Issue 7.png (140.13 KiB) Viewed 170 times
openBrain
Posts: 2372
Joined: Fri Nov 09, 2018 5:38 pm

Re: Fillet Issues - Links go out of allowed scope

Postby openBrain » Wed Jul 17, 2019 5:07 pm

I guess the edge you're trying to fillet is purely tangent with the side of your part, thus the geometric kernel can't solve that.
Could you modify your part so there is some clearance between the cylinder outer face and the "square" faces side ?
ConnorMoran
Posts: 6
Joined: Wed Jul 17, 2019 11:23 am

Re: Fillet Issues - Links go out of allowed scope

Postby ConnorMoran » Thu Jul 18, 2019 8:20 am

Not really as that reduces the fan diameter. It's based on this model. So I'm unsure why it's having such trouble...
I would use this but it isn't suitable. I need the fan and fan case parts separate.

https://drive.google.com/file/d/1GC-8EY ... sp=sharing

(File too big.)
kisolre
Posts: 1360
Joined: Wed Nov 21, 2018 1:13 pm

Re: Fillet Issues - Links go out of allowed scope

Postby kisolre » Thu Jul 18, 2019 9:18 am

Can I ask why are you designing that fan? As a modeling exercie, as exact recreation of that other file, as a production model, ... Does it have to be exactly like that?
One way I see is create basic shape without the cable channel and bolt holes with bigger top/bottom sides and the rupport ribs. Apply the necessary PD fillets (which cant be with variable radius - is this required/necessary?) Cut the desired external shape, add fan support, bolt holes and cable channel. All this in PartDesign.
ConnorMoran
Posts: 6
Joined: Wed Jul 17, 2019 11:23 am

Re: Fillet Issues - Links go out of allowed scope

Postby ConnorMoran » Thu Jul 18, 2019 10:04 am

A mix of modeling exercise and representation of a product. I have a model of a PC for it to fit in. The whole PC model is meant to be used for display purposes in VR/AR and such.

It's a bit of a learning exercise as to why it won't work with a variable radius since it's pretty clearly possible.
I can't add the fillet to the ribs if I add them after doing a fillet on the main cylinder. This is supposed to look good and polished as it'll be used to advertise system builds.
In the file I have added above there are sketches for the entire design. I can't just leave a load of edges looking flat as it'll look poor.

If I could convert the step file of the original design and turn it into a solid, I could cut the fan and case apart and use that. But alas, it is not a shell and thus cannot be converted into a solid.

I think I'll have to just overhaul the design. It's a pretty stupid limitation though. The PartDesign should have a variable radii option.
chrisb
Posts: 19594
Joined: Tue Mar 17, 2015 9:14 am

Re: Fillet Issues - Links go out of allowed scope

Postby chrisb » Thu Jul 18, 2019 10:08 am

ConnorMoran wrote:
Thu Jul 18, 2019 10:04 am
If I could convert the step file of the original design and turn it into a solid, I could cut the fan and case apart and use that. But alas, it is not a shell and thus cannot be converted into a solid.
So what is it? Most Step files I have seen here are already solidy so you can directly work in Part or PartDesign with them.
ConnorMoran
Posts: 6
Joined: Wed Jul 17, 2019 11:23 am

Re: Fillet Issues - Links go out of allowed scope

Postby ConnorMoran » Thu Jul 18, 2019 10:23 am

No idea. It's just a .STEP file I found.
Have a go, maybe I'm being stupid.

https://drive.google.com/file/d/1MpWdn8 ... sp=sharing

I just get:
Cannot convert <object> because Shape is not a shell.
chrisb
Posts: 19594
Joined: Tue Mar 17, 2015 9:14 am

Re: Fillet Issues - Links go out of allowed scope

Postby chrisb » Thu Jul 18, 2019 10:41 am

A geometry check takes almost forever and says it's a compound with two solids. It most probably cannot be used for further boolean operations because BOPCheck fails with lots of messages "BOP Algo GeomAbs_C0".