How to extract the shape to mesh from a compound

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uwestoehr
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How to extract the shape to mesh from a compound

Post by uwestoehr »

I have a 2D simulation where I combined 2 bodies as BooleanFragments. When I generate a Gmsh mesh from this, I get this warning:

Code: Select all

The mesh to shape is a boolean split tools Compound and the mesh has mesh region list.
Gmsh could return unexpected meshes in such circumstances.
It is strongly recommended to extract the shape to mesh from the Compound and use this one.
What does this mean? I could not find out how I can extract the shape from the BooleanFragments. Since I have 2D objects, I can also not use a Compound filter on the BooleanFragments.

Can anybody help me?
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uwestoehr
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Re: How to extract the shape to mesh from a compound

Post by uwestoehr »

uwestoehr wrote: Sat Aug 13, 2022 10:50 pm Can anybody help me?
I found out that the origin is from this thread: viewtopic.php?p=149467#p149467

From this thread here is the example file that fails:
geometry_on_faces4.fcstd
(284.77 KiB) Downloaded 34 times
For such cases (sketches on top of faces to define mesh regions) one must use a compound filter.

However, there are other cases what one must not use a compound filter and inputting a Boolean Fragments to Gmsh works well, like this one:
https://github.com/FreeCAD/FreeCAD/file ... ldWire.zip

Therefore I made this PR:
https://github.com/FreeCAD/FreeCAD/pull/8464
that changes the error message to a warning.
There I also changed the console outputs a bit to get warnings as such, logs only as logs, comment out some minor info mostly of interest for debugging FreeCAD etc.
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