Part Design Thickness - Non Implemented features

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onekk
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Re: Part Design Thickness - Non Implemented features

Post by onekk »

rahmanshaber wrote: Wed Aug 31, 2022 1:33 pm @mfro I made the same part in the Fusion 360 and it able to create shell with the part. I know both have different ways to do it.
Probably Fusion 360 and FC uses a different "modelling engine" and probably Fusion 360 is doing some "healing" on the model prior to apply the thickness tool or do some cheat ignoring some rules that break the model, as the list that are in the OCC documentation.

We are speaking of continuity of surfaces, C0 and C1 and similar terms.

See maybe:

https://dev.opencascade.org/doc/occt-7. ... _data.html

under Continuity of Curves and Surfaces


or for short:


C0 (GeomAbs_C0) - parametric continuity. It is the same as G0 (geometric continuity), so the last one is not represented by separate variable.
G1 (GeomAbs_G1) - tangent vectors on left and on right are parallel.
C1 (GeomAbs_C1) - indicates the continuity of the first derivative.
G2 (GeomAbs_G2) - in addition to G1 continuity, the centers of curvature on left and on right are the same.
C2 (GeomAbs_C2) - continuity of all derivatives till the second order.
C3 (GeomAbs_C3) - continuity of all derivatives till the third order.
CN (GeomAbs_CN) - continuity of all derivatives till the N-th order (infinite order of continuity).


An interesting reading could be:

https://dev.opencascade.org/doc/occt-7. ... algos.html

Your model are triggering some limitation of the "geometric kernel", the only way you have is to modify your model to comply with the "geometric kernel" requirement.

Regards

Carlo D.
GitHub page: https://github.com/onekk/freecad-doc.
- In deep articles on FreeCAD.
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Re: Part Design Thickness - Non Implemented features

Post by mfro »

rahmanshaber wrote: Wed Aug 31, 2022 1:33 pm @mfro I made the same part in the Fusion 360 and it able to create shell with the part. I know both have different ways to do it.
Can you post an image of that model so we know how it's supposed to look like? Maybe there are ideas about how to create it without thickness.
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Markus
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onekk
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Re: Part Design Thickness - Non Implemented features

Post by onekk »

mfro wrote: Wed Aug 31, 2022 2:51 pm Can you post an image of that model so we know how it's supposed to look like? Maybe there are ideas about how to create it without thickness.
probably this:

https://forum.freecadweb.org/viewtopic. ... 19#p622519

Or probably not, as you post is newer than the post on the model is, but maybe OP has amended the post after your answer.

Regards

Carlo D.
GitHub page: https://github.com/onekk/freecad-doc.
- In deep articles on FreeCAD.
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Re: Part Design Thickness - Non Implemented features

Post by mfro »

Have seen that, but I wanted to see how the model is supposed to finally look like as it's not clear (at least to me) where and how the thickness should be applied
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Markus
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Re: Part Design Thickness - Non Implemented features

Post by GeneFC »

Here is a screenshot of "works" file with 80% transparency added.

Thickness.JPG
Thickness.JPG (31.83 KiB) Viewed 1162 times

Gene
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Shalmeneser
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Re: Part Design Thickness - Non Implemented features

Post by Shalmeneser »

Thickness tool works but not with the MultiTransform (but CheckGeometry is sad).

MultiTransform can be sensitive.
Thickness is very sensitive.
MultiTransform+Thickness will be sensitive.
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rahmanshaber
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Re: Part Design Thickness - Non Implemented features

Post by rahmanshaber »

Here is how it looks like, i made this in fusion 360 in 10 mins. I used the same dimensions and method to make the model in fusion 360 and i can create the shell.
tt.jpg
tt.jpg (38.57 KiB) Viewed 1141 times
rr.jpg
rr.jpg (26.1 KiB) Viewed 1141 times
@mfro I couldn't find anyother way to finish this part so thickness tool can work.

@onekk I believe so, they are fixing the model so it won't break if the fix is minor. I don't understand what the doc is saying and it's beyond my understanding, i just want the app to work for me so i can finish my work.

Why OCC can't tell me what's/where's the issue is? the report view says "Recompute failed! Please check report view." That's a joke. report view is asking me to check report view.
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Re: Part Design Thickness - Non Implemented features

Post by onekk »

Yes it is a joke, as probably there is no message to show.

This is s thing that I don't know for sure.

Documentation of OCC could of some help when FC documentation is lacking.

But here you will find some help.

Someone has asked for the model to see if something could be done to modify the model, see some post above by mfro.

Regards

Carlo D.
GitHub page: https://github.com/onekk/freecad-doc.
- In deep articles on FreeCAD.
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Re: Part Design Thickness - Non Implemented features

Post by mfro »

I understand @Shalmeneser has found a way to trick Thickness into working, but I would also assume the model is simple enough to completely avoid it: create a "negative" volume that resembles the Thickness and do a boolean cut. Shouldn't take much longer.
Cheers,
Markus
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Re: Part Design Thickness - Non Implemented features

Post by mfro »

chrisb wrote: Wed Aug 31, 2022 2:25 pm Great find! Would you mind adding this to the wiki :mrgreen: ?
My pleasure! But I must admit I don't have even the slightest idea on how to do that.
Cheers,
Markus
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