shaise/FreeCAD_SheetMetal

Unfold option Issue

jaisekjames opened this issue · 12 comments

jaisekjames commented

See Issue

https://forum.freecadweb.org/viewtopic.php?f=22&t=25281&start=150#p279502
please change from
unfoldLength = ( bendR + kfactor * thk / 2.0 ) * bendA * math.pi / 180
to
unfoldLength = ( bendR + kfactor * thk / 2.0 ) * bendA * math.pi / 180.0
Add decimal place to 180.

shaise commented

Thanks! I will take a look

shaise commented

Hi,

The 180.0 is not the problem. The problem is difference between European and American standard of k_facror (one of them is 1/2 the other). I have reverted it to the European standard, which is compatible with Ulrich's original unfolder script. Now both unfolding from your system, and Ulrich's system match.

jaisekjames commented

Thank you

f3nix commented

Thanks! :)

I have tested the changes and here are my observations.

Cases 1 and 3 work as expected now. 👍
I have a question about case 2. Should it use the kfactor set in the kfactor parameter (property).

image

It seems it uses 0.65 in this instance.

up Face7 k-factor: 0.65

Cheers,
Mateusz

shaise commented

The k factor in the properties are total different system and works only on sheetmetal prefolded using the sheetmetal WB. If you make a sheetmetal model using another system, you can only unfold it using the unfold button. The unfold button uses its own K-factor, and its the same factor for all folds. The properties system can set a different k factor to each fold.

f3nix commented

Ok. Here is what I'm doing.

  1. Create body and sketch.
  2. Draw a rectangle (82mmx90mm).
  3. Pad it (4mm).
  4. Create a bend.
  5. Change default properties:
    • length: 82mm
    • radius: 4mm
    • kfactor: 0,86
    • reliefd: 0mm
    • reliefw: 0mm
  6. Select face and click "Flatten folded sheet metal object".

The unfolded length is 182,33mm (which is different than other two unfold cases).

Report view says:
up Face7 k-factor: 0.65

It does not use the 0,86 kfactor that I have set in the bend property.

Is it the intended behaviour (workflow) or am I doing something wrong?

Here is the example file: L-bracket-final.zip

OS: Debian GNU/Linux buster/sid
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.15703 (Git)
Build type: Debug
Branch: master
Hash: 80f82b59db1bae91115921d7da3190f855e1041f
Python version: 2.7.15+
Qt version: 5.11.3
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: Polish/Poland (pl_PL)

Cheers,
Mateusz

shaise commented

Sorry if I wasn't clear,

The unfold button disregards ALL fold properties, and works with its own k-factor system.
The only way to use the k-factor in the the properties, is to set the unfold to true in the properties as well. This means, and I know its tedious, that if you want to unfold the entire object using the k-factor in the properties, you need to go fold by fold and set the unfold property to true as well.

f3nix commented

Thanks for clarifying. I think this issue has been resolved.

Thank you again! :)

Cheers,
Mateusz

ceremcem commented

@shaise

The unfold button disregards ALL fold properties, and works with its own k-factor system.
The only way to use the k-factor in the the properties, is to set the unfold to true in the properties as well. This means, and I know its tedious, that if you want to unfold the entire object using the k-factor in the properties, you need to go fold by fold and set the unfold property to true as well.

Wow! I was about to open an issue about "k-factor is not regarded while unfolding" and I just saw this explanation. What is the use case of this behavior? Why isn't the k-factor from the bend properties simply used while unfolding?

ceremcem commented

@jaisekjames I now think the issue is solved.

luzpaz commented

@shaise can this ticket be resolved?

shaise commented

yes, I think it can be closed