[Gmsh] Stuck in infinite loop on BooleanDifference?

[Gavin Ridley]

Hi gmsh community,

I'm trying to make a multi-region mesh that consists of a few concentric
spheres, plus what are pipes leading into one of the spheres. This is
intended to eventually be a coolant channel. Around some fuel for a space
reactor design.

The CSG functionality is great for this, but seems to get caught in an
infinite loop after reading the last line of this input:

////////////////////////////
SetFactory("OpenCASCADE");

// Dimensions from core optimization
rfuel = .0505;
rvess = .0555;
rcool  = .06135;
rsteel = .06635;
rrefl = .19705;

// These pipes could have their radii varied to get different effects
rpipetop = 5.229/2.0;
rpipebot = 5.229/2.0;
pipeWallThick = 0.005;

// z coordinates of bottom of cylinder to make it match with spherical
vessel
hcyltop = Sqrt(rcool*rcool-rpipetop*rpipetop);
hcylbot = Sqrt(rcool*rcool-rpipebot*rpipebot);

// Length of pipe at top and bottom to capture any recirculations
topdevelopLength = .03;
botdevelopLength= .03;

// "jawbreaker"
Sphere(1) = {0.0, 0.0, 0.0, rfuel};
p() = PointsOf{ Volume{1}; };
Characteristic Length{p()} = rfuel/4.0;
Physical Volume("fuel") = {1};

// vessel
Sphere(2) = {0.0, 0.0, 0.0, rvess};
BooleanDifference(3) = {Volume{2}; Delete;}{Volume{1};};
p() = PointsOf{ Volume{3}; };
Characteristic Length{p()} = (rvess-rfuel)/2.0;
Physical Volume("tantaloy") = {3};

// sodium
Sphere(4) = {0.0, 0.0, 0.0, rcool};
BooleanDifference(5) = {Volume{4};}{Volume{3,1};};
Cylinder(6) = {0.0, 0.0, hcyltop, 0.0, 0.0, hcyltop+topdevelopLength,
rpipetop};
BooleanDifference(7) = {Volume{6}; Delete;}{Volume{4}; Delete;};
//////////////////////////////////////////

I'm trying to cut a sphere out of the bottom of a cylinder for that (7)
entity. If it helps the developers at all, here's what the stack looks like
in the infinite loop.

#0  0x00007fffefdbb8c4 in __memset_avx2_unaligned_erms () from
/usr/lib/libc.so.6
#1  0x00007fffefce711b in calloc () from /usr/lib/libc.so.6
#2  0x00007ffff120ad31 in Standard_MMgrRaw::Allocate(unsigned long) ()
   from /opt/opencascade/lib/libTKernel.so.0
#3  0x00007ffff257ace7 in TopExp_Explorer::TopExp_Explorer() ()
   from /opt/opencascade/lib/libTKBRep.so.0
#4  0x00007ffff2f47c2c in
BRepClass3d_SolidExplorer::FindAPointInTheFace(TopoDS_Face const&, gp_Pnt&,
double&, double&, double&, gp_Vec&, gp_Vec&) ()
   from /opt/opencascade/lib/libTKTopAlgo.so.0
#5  0x00007ffff2f48cd6 in
BRepClass3d_SolidExplorer::PointInTheFace(TopoDS_Face const&, gp_Pnt&,
double&, double&, double&, int&, Handle_BRepAdaptor_HSurface const&,
double, double, double, double, gp_Vec&, gp_Vec&) const () from
/opt/opencascade/lib/libTKTopAlgo.so.0
#6  0x00007ffff2f49a3f in BRepClass3d_SolidExplorer::OtherSegment(gp_Pnt
const&, gp_Lin&, double&) () from /opt/opencascade/lib/libTKTopAlgo.so.0
#7  0x00007ffff2f45dbf in
BRepClass3d_SClassifier::Perform(BRepClass3d_SolidExplorer&, gp_Pnt const&,
double) () from /opt/opencascade/lib/libTKTopAlgo.so.0
#8  0x00007ffff353b77c in void
OSD_Parallel::For<BOPCol_ContextFunctor<BOPAlgo_VertexSolid,
BOPCol_NCVector<BOPAlgo_VertexSolid>, Handle_IntTools_Context,
IntTools_Context> >(int, int, BOPCol_ContextFunctor<BOPAlgo_VertexSolid,
BOPCol_NCVector<BOPAlgo_VertexSolid>, Handle_IntTools_Context,
IntTools_Context> const&, unsigned int) () from
/opt/opencascade/lib/libTKBO.so.0
#9  0x00007ffff3539d07 in BOPAlgo_PaveFiller::PerformVZ() ()
   from /opt/opencascade/lib/libTKBO.so.0
#10 0x00007ffff3536f20 in BOPAlgo_PaveFiller::PerformInternal() ()
   from /opt/opencascade/lib/libTKBO.so.0
#11 0x00007ffff3536cef in BOPAlgo_PaveFiller::Perform() ()
   from /opt/opencascade/lib/libTKBO.so.0
#12 0x00007ffff35c37d5 in BRepAlgoAPI_BooleanOperation::Build() ()
   from /opt/opencascade/lib/libTKBO.so.0
#13 0x0000555555a5ed08 in OCC_Internals::booleanOperator
(this=0x555556ae5330, tag=7,
    op=OCC_Internals::Difference, objectDimTags=std::vector of length 1,
capacity 1 = {...},
    toolDimTags=std::vector of length 1, capacity 1 = {...},
    outDimTags=std::vector of length 0, capacity 0,
    outDimTagsMap=std::vector of length 0, capacity 0, removeObject=true,
removeTool=true)
    at /home/gavin/code/gmsh/Geo/GModelIO_OCC.cpp:2421
#14 0x0000555555eef8ee in gmsh_yyparse () at Gmsh.y:4081
#15 0x00005555558c4465 in ParseFile (fileName="pulsr.geo",
close=close at entry=true,

    warnIfMissing=warnIfMissing at entry=false) at
/home/gavin/code/gmsh/Common/OpenFile.cpp:199
#16 0x0000555555a014fd in GModel::readGEO (name="pulsr.geo")
    at /home/gavin/code/gmsh/Geo/GModel.cpp:2716
#17 0x00005555558c42b3 in MergeFile (fileName="pulsr.geo",
    warnIfMissing=warnIfMissing at entry=false,
setBoundingBox=setBoundingBox at entry=true,
    importPhysicalsInOnelab=importPhysicalsInOnelab at entry=true)
    at /home/gavin/code/gmsh/Common/OpenFile.cpp:508
#18 0x00005555558c58d7 in OpenProject (fileName="pulsr.geo")
    at /home/gavin/code/gmsh/Common/OpenFile.cpp:716
#19 0x000055555586e6eb in GmshBatch () at
/home/gavin/code/gmsh/Common/GmshGlobal.cpp:266
#20 0x0000555555861dc7 in main (argc=7, argv=0x7fffffffda08)

So, is this user, or code error? Any advice would be greatly appreciated.

-- 
Thanks,
Gavin Ridley
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