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shaise / FreeCAD_SheetMetal

A simple sheet metal workbench for FreeCAD
http://theseger.com/projects/2015/06/sheet-metal-addon-for-freecad/
GNU Lesser General Public License v2.1
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"Error Starting: invalid thickness" when unfolding #260

Closed nicocesar closed 1 year ago

nicocesar commented 1 year ago

I'm using FreeCAD 0.20 Revision: 14555 (Git shallow) released 23.12.2022 under Linux with sheet metal add-on V0.2.60

When I did unfold I get this output in the console: 

Engineering mode is not enabled.
Manual K-factor is being used: 0.40 (ansi)
Error Starting: invalid thickness at Face4
exception at line 3298("'NoneType' object has no attribute 'Edges'",)
("'NoneType' object has no attribute 'Edges'",)
Traceback (most recent call last):
  File "/home/nico/snap/freecad-realthunder/common/.FreeCAD/Mod/sheetmetal/SheetMetalUnfolder.py", line 3298, in accept
    foldLines = foldComp.Edges
AttributeError: 'NoneType' object has no attribute 'Edges'

with a generic "Error Starting: invalid thickness at Face4"

The file is attached.

Could this be a consequence of adding a formula as the thickness(Lenght) of the pad?

unfold_error.zip

nicocesar commented 1 year ago

~~One extra datapoint: It seems formulas expressions like "a * b" make this failure. ~~

I think I found my problem: If different walls are touching, the total thickness is taking into account. I added a 0.01 gap between my touching folds and solved the problem.

I don't know if this is expected or the add-on can be improved somehow

shaise commented 1 year ago

The reason the unfolding failed is because the lips of the side folds touches the side wall with no spacing. This overlap of faces sometimes causes freecad to fail some operations (such as boolean operations that are used with sheetmetal) If you change the thickness to 1.99mm or change other dimensions to prevent this overlap, the folding will succeed.

luzpaz commented 1 year ago

Closing ticket