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Full Version: Fillet & Loft

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From: krass
29 Aug   [#1]
One more question, if you please.
Given: a figure with multidirectional angles.
When I try to assign a fillet to an edge that connects corners, I get an error.


But, if I round the corners on the shape curves with the same radius and then apply Loft, the edge is formed as needed.


I am not a fun of the new Plastcity product, but Fillet of a similar place works there.
Although with some funny "overlap" ...

The question is - is it possible to do this using Fillet in MOI3D?

Image Attachments:
Screenshot_32.png 


From: Psygorn (DRILLBIT)
29 Aug   [#2] In reply to [#1]
Hello,

But is it too hard to fillet the outlines first and then perform loft? :-)
From: krass
29 Aug   [#3] In reply to [#2]
Maybe.
But first - try to make fillets in such a finished part.
I am happy to teach.

Attachments:
tst01.3dm

Image Attachments:
Screenshot_33.png 


From: Michael Gibson
29 Aug   [#4] In reply to [#1]
Hi krass,

re:
> Given: a figure with multidirectional angles.

Can you please post the .3dm model file with your figure in it?

Thanks,
- Michael
From: krass
29 Aug   [#5] In reply to [#4]

Image Attachments:
Screenshot_34.png 


From: Michael Gibson
29 Aug   [#6] In reply to [#5]
Hi krass, sorry I didn't see that your model was attached later in the thread.

Yes, that's a particularly difficult case to fillet. Fillets shrink down to zero width at spots where 2 surfaces are tangent to each other and you've got that situation just at one point right in the middle of where the fillet wants to go.

That's an unusual situation and I don't expect that MoI's filleter will be able to handle it. Probably it will be difficult in many CAD programs because they don't really expect to process a discontinuity right in the middle of the fillet.

So for that kind of situation you would need to use some other method than the regular edge fillet. Filleting curves and doing a loft as you already did is a good way. You could also cut away some space and put in a blend surface, like this:







- Michael

Attachments:
tst02.3dm

Image Attachments:
krass_fillet_discontinuity1.jpg  krass_fillet_discontinuity2.jpg  krass_fillet_discontinuity3.jpg 


From: Michael Gibson
29 Aug   [#7] In reply to [#5]
Hi krass, you can get part of the fillet in Moi if you separate out these faces from the rest of the object:



Then part of the fillet can get generated:





But probably your loft method is giving a better result than a real fillet which is going to collapse down to a point right in the middle.

- Michael

Image Attachments:
krass_fillet_discontinuity4.jpg  krass_fillet_discontinuity5.jpg  krass_fillet_discontinuity6.jpg 


From: Frenchy Pilou (PILOU)
29 Aug   [#8]
Maybe like this ;)


Kill the 2 faces

Fillet lateral edges (5) if you want same general fillet take Max 3.5
- Kill Face - Redraw curve by extremities - middle arcs... so 5 points ...Make Plane
Same other side
Sweep the 2 edges by Bottom / Top
Union All
Fillets wanted here 1



Quasi Max Fillet 3.5



From: krass
29 Aug   [#9] In reply to [#6]
Thank you for your time and detailed explanation! I will keep in mind - for the future - that this is not a typical case for MOI and take this into account when designing.


I just looked at how this chituation is solved by means of Plasticity, I decided to repeat it in MY, thinking that everything is simple and ... oops ..
Thanks again !!

Image Attachments:
Screenshot_32.png 


From: krass
29 Aug   [#10] In reply to [#7]
By the way, in the process of experimenting with fillets, I noticed an interesting point.
The adjoining chamfer in MOI is also formed with a radius (in this case, the chamfer "splits")


In plasticity, on the contrary, an angle is formed at the junction.
Sometimes it's useful, sometimes it's not.



The question is - is it possible to form the same angle in MOI or is it not provided constructively?

Image Attachments:
Screenshot_35.png  Screenshot_36.png 


From: Michael Gibson
29 Aug   [#11] In reply to [#9]
Hi krass,

> I just looked at how this chituation is solved by means of Plasticity, I decided to repeat it in MY, thinking
> that everything is simple and ... oops ..

Yes, that's interesting that it works in Plasticity. I tested it in Rhino and ViaCAD and it didn't work in either of those.

It's definitely not a simple case with it collapsing down to a single point in the middle of the fillet surface.

- Michael
From: Michael Gibson
29 Aug   [#12] In reply to [#10]
Hi krass,

re:
> The question is - is it possible to form the same angle in MOI or is it not provided constructively?

You can in some cases enable the "Straight corners" option to inhibit the creation of corner juncture patches but it's not very reliable.

But in cases where it works it goes like this:





Having corner junctures enabled usually helps make fillets work better in MoI so if you need that type of control very often you should probably plan on exporting to a different app and then filleting there and then bring it back into MoI.

- Michael

Image Attachments:
krass_fillet_corners1.jpg  krass_fillet_corners2.jpg 


From: krass
29 Aug   [#13]
I recorded a short video of solving the problem and getting the desired result.
Maybe someone will be useful.

https://youtu.be/Rke7gavSw7o
From: krass
29 Aug   [#14] In reply to [#12]
Yes, of course I know about the "Straight corners" function in the fillet, but this is in the case of the "outer fillet".
And here is just the case of the "inner" radius, that's why I asked.
From: krass
29 Aug   [#15] In reply to [#8]
Frenchy, thanks! Very interesting experiments!
From: krass
1 Sep   [#16]
Michael, I don't know why, but I can't add images and files to the forum anymore.
When added, it writes "Out of space" ... Where can I fix it?
Sorry for being a little off topic.
From: bemfarmer
1 Sep   [#17] In reply to [#16]
Hi krass,

We are all limited in the amount of memory we can upload attachments to.
So it is necessary to delete some prior posted attachments.
Pictures can be replaced by alternate storage sites, such as imgbox.com, which frees up some attachment memory.
(See Pilou posts, for example).

I've used imgbox in the last few months, as a substitute for posting picture attachments,
but have never mastered how to use it, or how it works.
It seems like a user of imgbox should keep a list of addresses, URL's, of pictures that the user has uploaded to the imgbox site?
As well as backup copies of images.

- Brian
https://imgbox.com/help
https://techgyo.com/imgbox-free-image-hosting-service-with-versatile-features
From: krass
1 Sep   [#18] In reply to [#17]
2 bemfarmer

Hello, thanks! I do it!
From: krass
1 Sep   [#19]
Michael, another interesting fillet puzzle.

I will write here so as not to produce topics.

So solid on the right.
I add some fillets to it and get such a solid as on the left.



Next, on the solid on the right, I CAN continue doing fillets (red, top)
And on the solid on the left - I don’t know why - I can’t make a single fillet anymore (even on the upper edge, like on the right)

Question - what did I break?

Attachments:
fillet_test_03.3dm

Image Attachments:
Screenshot_7.png 


From: Psygorn (DRILLBIT)
1 Sep   [#20] In reply to [#3]
Yes, I admit for the finished version it is hard to have those fillets!

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