[Bug tracker #4360] Bug in 0.19? BOPcheck fails on pocket of ShapeString

[Syres]

Sorry I can't test by myself ATM, but it would be interesting to know whether a lone ShapeString also produces the same error when checked.
If not, does a Part/Extrude of a ShapeString do ? If not, does a PartDesign/Pad do ?

@TedM has done these tests already see above https://forum.freecadweb.org/viewtopic. ... 88#p403083 I have confirmed that the lone Shapestring extruded fails in the same way

[chrisb]

Part Extrude of ArialBold "R" creates an error as well.

OS: macOS High Sierra (10.13)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.21125 (Git)
Build type: Release
Branch: master
Hash: 40600a55c2fe71ff589be677f6e427ccc937d003
Python version: 3.8.2
Qt version: 5.12.5
Coin version: 4.0.0
OCC version: 7.4.0
Locale: C/Default (C)

[Syres]

So any letter that has a BSpline in it's wire like the problem that previously existed in Path>Engaving fails but a small k suceeds because it's all straight lines??

[chrisb]

So any letter that has a BSpline in it's wire like the problem that previously existed in Path>Engaving fails but a small k suceeds because it's all straight lines??

That's how it seems. I am surpised that converting to a Sketch helps.

[tanderson69]

So any letter that has a BSpline in it's wire like the problem that previously existed in Path>Engaving fails but a small k suceeds because it's all straight lines??

That's how it seems. I am surpised that converting to a Sketch helps.

This might be the same thing:
bop check bug

[fc_tofu]

Sorry I can't test by myself ATM, but it would be interesting to know whether a lone ShapeString also produces the same error when checked.
If not, does a Part/Extrude of a ShapeString do ? If not, does a PartDesign/Pad do ?

A plane/plain ShapeString object donnot cause BOPcheck error as mentioned by OP.

On the optimistic side, a BOPcheck-failed ShapeString extrude when exported as STEP and reimport back, error disappear.

[chrisb]

I think it was user Quaoar who pointed out that a failing BOPCheck does not mean that the object is in error. It sais as far as I can remember that with some increased probability a subsequent boolean operation may fail.

[openBrain]

What would be efficient is to have this summarized in the ticket so developers are easily aware of this test configurations.
If I'm correct :

• Lone ShapeString => No error
• ShapeString with Part/Extrude => Error
• ShapeString with PartDesign/Pad => Error
• ShapeString with PartDesign/Pocket => Error
• Any failing case above exported as STEP then reimported => No error
• ShapeString converted to sketch then Extrude/Pad/Pocket => No error

As an extra clue, characters with only straight lines don't trigger error. Looks like it comes from NURBS (I saw 'B-Splines' in the thread, but are you sure it's really only B-Splines ?)

[wandererfan]

This looks to be at least partly an Orientation problem. If I check the Orientation of the components of "B", I get:

Code: Select all

> face orientation: Reversed
 >>wire orientation: Reversed
 >>>edge orientation: Reversed
 >>>edge orientation: Reversed
...
 >>>edge orientation: Reversed
 >>wire orientation: Reversed
 >>>edge orientation: Reversed
 >>>edge orientation: Reversed
 ...
  >>>edge orientation: Reversed
 >>wire orientation: Reversed
 >>>edge orientation: Reversed
 >>>edge orientation: Reversed
 ...
  >>>edge orientation: Reversed

The Face should be forward, 1 Wire should be forward, 2 Wires should be reversed. Edge Orientation should depend on whether the associated Wire is an island or a lake.

As Roman Lygin says: "if an edge is forward then material is on the left, if reversed, material is on the right"

Draft.ShapeString.makeFaces() is the first place to look.

[TedM]

Sorry I can't test by myself ATM, but it would be interesting to know whether a lone ShapeString also produces the same error when checked.
If not, does a Part/Extrude of a ShapeString do ? If not, does a PartDesign/Pad do ?

@TedM has done these tests already see above https://forum.freecadweb.org/viewtopic. ... 88#p403083 I have confirmed that the lone Shapestring extruded fails in the same way

Actually, I did not previously test this. I just did this and the analysis (with full BOP Check) of a bare ShapeString succeeds with no errors.

I also confirmed that letters with only straight lines do not cause the error and that Part/Extrude of the ShapeString also fails.

I have updated the ticket with the information collected here.

Thanks, everyone, for the attention on this.