[Gmsh] Coherence 'could not find extruded vertex' error
Hello,
Sorry to bother everybody again.
I'm a beginner and I seem to run in on one error after another. I'm using GMSH
4.7.0 (I came across GMSH trough the onelab website) on Windows 10.
See the script below (from a bigger 3D project where I try to narrow down the
errors I get).
I get a good 3D mesh but at the curve where the two objects meet, the mesh is
not aligned.
Using the coherence command I get a large list of errors of the type:
Error : could not find extruded vertex (0.08443279255020152,
-0.053826794978966, 0).
Yet, if I change the point y-coordinates to a positive number:
Point(23) = {0, 0.1, 0};
Point(24) = {0, 0.05, 0};
Point(25) = {0, 0.05, WanD};
Point(26) = {0, 0.1, WanD};
All works as expected.
Thanks for the help.
Bart
---
KanR = DefineNumber[ 0.1, Name "Parameters/KanR" ];
WanD = DefineNumber[ 0.2, Name "Parameters/WanD" ];
KanMeshsize = DefineNumber[ 0.01, Name "Parameters/KanMeshsize" ];
SetFactory("OpenCASCADE");
Rectangle(1) = {-2.5, -2.5, 0, 5, 5, 0};
Circle(5) = {0, 0, 0, KanR, 0, 2*Pi};
Curve Loop(2) = {5};
Plane Surface(2) = {2};
BooleanDifference{ Surface{1}; Delete; }{ Surface{2}; Delete; }
Extrude {0, 0, WanD } {
Surface{1};
}
Point(23) = {0, -0.1, 0};
Point(24) = {0, -0.05, 0};
Point(25) = {0, -0.05, WanD};
Point(26) = {0, -0.1, WanD};
Line(32) = {23, 24};
Line(33) = {24, 25};
Line(34) = {25, 26};
Line(35) = {26, 23};
Curve Loop(30) = {34, 35, 32, 33};
Plane Surface(14) = {30};
Extrude {{0, 0, 1}, {0, 0, 0}, Pi} {
Surface{14}; Layers{25};
}
Field[1] = Distance;
Field[1].EdgesList = {5};
Field[1].NNodesByEdge = 50;
Field[2] = Threshold;
Field[2].DistMax = 2.5;
Field[2].DistMin = 0;
Field[2].IField = 1;
Field[2].LcMax = 0.25;
Field[2].LcMin = KanMeshsize ;
Background Field = 2;
Mesh.CharacteristicLengthExtendFromBoundary = 0;
Mesh.CharacteristicLengthFromPoints = 0;
Mesh.CharacteristicLengthFromCurvature = 0;
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Re: [Gmsh] Coherence 'could not find extruded vertex' error
On Mon, 2020-08-17 at 08:16 +, Bart Deschoolmeester wrote: > Hello, > > Sorry to bother everybody again. > > I’m a beginner and I seem to run in on one error after another. I’m > using GMSH 4.7.0 (I came across GMSH trough the onelab website) on > Windows 10. How does the future look Martin? Sad to see that people sill use Windows :-( > > > See the script below (from a bigger 3D project where I try to narrow > down the errors I get). > > I get a good 3D mesh but at the curve where the two objects meet, the > mesh is not aligned. > > Using the coherence command I get a large list of errors of the type: > > Error : could not find extruded vertex (0.08443279255020152, > -0.053826794978966, 0). Try to re-use line 18 for the last extrude instead of creating a new edge 35. -- jeremy theler www.seamplex.com ___ gmsh mailing list gmsh@onelab.info http://onelab.info/mailman/listinfo/gmsh
Re: [Gmsh] Coherence 'could not find extruded vertex' error
Dear Bart,
What are you trying to achieve? As Jeremy explained, your geometry is
non-conformal. Do you want to create a conformal mesh? If so you'll need to
have a conformal geometry first.
Christophe
> On 17 Aug 2020, at 10:16, Bart Deschoolmeester
> wrote:
>
> Hello,
> Sorry to bother everybody again.
> I’m a beginner and I seem to run in on one error after another. I’m using
> GMSH 4.7.0 (I came across GMSH trough the onelab website) on Windows 10.
>
> See the script below (from a bigger 3D project where I try to narrow down the
> errors I get).
> I get a good 3D mesh but at the curve where the two objects meet, the mesh is
> not aligned.
> Using the coherence command I get a large list of errors of the type:
> Error : could not find extruded vertex (0.08443279255020152,
> -0.053826794978966, 0).
>
> Yet, if I change the point y-coordinates to a positive number:
>Point(23) = {0, 0.1, 0};
> Point(24) = {0, 0.05, 0};
> Point(25) = {0, 0.05, WanD};
> Point(26) = {0, 0.1, WanD};
>
> All works as expected.
>
> Thanks for the help.
> Bart
>
>
> ---
>
> KanR = DefineNumber[ 0.1, Name "Parameters/KanR" ];
> WanD = DefineNumber[ 0.2, Name "Parameters/WanD" ];
> KanMeshsize = DefineNumber[ 0.01, Name "Parameters/KanMeshsize" ];
> SetFactory("OpenCASCADE");
> Rectangle(1) = {-2.5, -2.5, 0, 5, 5, 0};
> Circle(5) = {0, 0, 0, KanR, 0, 2*Pi};
> Curve Loop(2) = {5};
> Plane Surface(2) = {2};
> BooleanDifference{ Surface{1}; Delete; }{ Surface{2}; Delete; }
> Extrude {0, 0, WanD } {
> Surface{1};
> }
>
> Point(23) = {0, -0.1, 0};
> Point(24) = {0, -0.05, 0};
> Point(25) = {0, -0.05, WanD};
> Point(26) = {0, -0.1, WanD};
> Line(32) = {23, 24};
> Line(33) = {24, 25};
> Line(34) = {25, 26};
> Line(35) = {26, 23};
> Curve Loop(30) = {34, 35, 32, 33};
> Plane Surface(14) = {30};
> Extrude {{0, 0, 1}, {0, 0, 0}, Pi} {
> Surface{14}; Layers{25};
> }
>
> Field[1] = Distance;
> Field[1].EdgesList = {5};
> Field[1].NNodesByEdge = 50;
> Field[2] = Threshold;
> Field[2].DistMax = 2.5;
> Field[2].DistMin = 0;
> Field[2].IField = 1;
> Field[2].LcMax = 0.25;
> Field[2].LcMin = KanMeshsize ;
>
> Background Field = 2;
>
> Mesh.CharacteristicLengthExtendFromBoundary = 0;
> Mesh.CharacteristicLengthFromPoints = 0;
> Mesh.CharacteristicLengthFromCurvature = 0;
> ___
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—
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science
http://www.montefiore.ulg.ac.be/~geuzaine
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Re: [Gmsh] Coherence 'could not find extruded vertex' error
Thank you again Jeremy,
You’re solution (see below as I understand it) works.
Yet, I have no clue why yours does and mine doesn’t.
Bart.
KanR = DefineNumber[ 0.1, Name "Parameters/KanR" ];
WanD = DefineNumber[ 0.2, Name "Parameters/WanD" ];
KanMeshsize = DefineNumber[ 0.01, Name "Parameters/KanMeshsize" ];
SetFactory("OpenCASCADE");
Rectangle(1) = {-2.5, -2.5, 0, 5, 5, 0};
Circle(5) = {0, 0, 0, KanR, 0, 2*Pi};
Curve Loop(2) = {5};
Plane Surface(2) = {2};
BooleanDifference{ Surface{1}; Delete; }{ Surface{2}; Delete; }
Extrude {0, 0, WanD } {
Surface{1};
}
Point(15) = {0.05, 0, 0};
Point(16) = {0.05, 0, WanD};
Line(20) = {5, 15};
Line(21) = {15, 16};
Line(22) = {16, 14};
Curve Loop(8) = {21, 22, -18, 20};
Plane Surface(8) = {8};
Extrude {{0, 0, 1}, {0, 0, 0}, Pi} {
Surface{8}; Layers{25};
}
Field[1] = Distance;
Field[1].EdgesList = {5};
Field[1].NNodesByEdge = 50;
Field[2] = Threshold;
Field[2].DistMax = 2.5;
Field[2].DistMin = 0;
Field[2].IField = 1;
Field[2].LcMax = 0.25;
Field[2].LcMin = KanMeshsize ;
Background Field = 2;
Mesh.CharacteristicLengthExtendFromBoundary = 0;
Mesh.CharacteristicLengthFromPoints = 0;
Mesh.CharacteristicLengthFromCurvature = 0;
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Re: [Gmsh] Coherence 'could not find extruded vertex' error
Thanks Christophe,
I am trying to work with GMSH. But as I run into many errors I have only two
possible answers:
1/ GMSH is error prone (which I doubt somewhat 😉).
2/ I am not grasping some fundamental concepts, which makes GMSH unintuitive to
me.
So now I would like to get my head around these fundamental concepts.
In your answer you talk about 'non-conformal geometry'. I have no idea what
that means. The only thing I could find in the manual is:
" A finite element mesh of a model is a tessellation of its geometry by simple
geometrical elements of various shapes (in Gmsh: lines, triangles, quadrangles,
tetrahedra, prisms, hexahedra and pyramids), arranged in such a way that if two
of them intersect, they do so along a face, an edge or a node, and never
otherwise. This defines a so-called “conformal” mesh."
"// By default, across geometrical dimensions meshes generated by Gmsh are only
// conformal if lower dimensional entities are on the boundary of higher
// dimensional ones (i.e. if points, curves or surfaces are part of the boundary
// of volumes)."
I think my geometry conforms to this.
Only hidden in t16.geo I find "a conformal manner (without creating duplicate
interfaces)". Aha! So, if I understand this correct, conformal also means that
if entities intersect, they do this along a unique (the same) face, edge, node.
Maybe this should be emphasized in the manual.
So I've rewritten the script to make sure this is no longer the case (see below)
But I kept getting the same error. So I'm still missing something. What?
Thank you.
--
KanR = DefineNumber[ 0.1, Name "Parameters/KanR" ];
WanD = DefineNumber[ 0.2, Name "Parameters/WanD" ];
KanMeshsize = DefineNumber[ 0.01, Name "Parameters/KanMeshsize" ];
SetFactory("OpenCASCADE");
Rectangle(1) = {-2.5, -2.5, 0, 5, 5, 0};
Circle(5) = {0, 0, 0, KanR, 0, 2*Pi};
Curve Loop(2) = {5};
Plane Surface(2) = {2};
Extrude {0, 0, WanD } {
Surface{1,2};
}
Point(23) = {0, -0.1, 0};
Point(24) = {0, -0.05, 0};
Point(25) = {0, -0.05, WanD};
Point(26) = {0, -0.1, WanD};
Line(32) = {25, 24};
Line(33) = {24, 23};
Line(34) = {23, 26};
Line(35) = {26, 25};
Curve Loop(30) = {32, 33, 34, 35};
Plane Surface(14) = {30};
Extrude {{0, 0, 1}, {0, 0, 0}, Pi} {
Surface{14}; Layers{25};
}
BooleanFragments{ Volume{3}; Volume{1}; Delete; }{ Volume{2}; Delete; }
Delete { Volume {5 }; }
Delete { Surface {10,14 }; }
Field[1] = Distance;
Field[1].EdgesList = {16,17,18};
Field[1].NNodesByEdge = 50;
Field[2] = Threshold;
Field[2].DistMax = 2.5;
Field[2].DistMin = 0;
Field[2].IField = 1;
Field[2].LcMax = 0.25;
Field[2].LcMin = KanMeshsize ;
Background Field = 2;
Mesh.CharacteristicLengthExtendFromBoundary = 0;
Mesh.CharacteristicLengthFromPoints = 0;
Mesh.CharacteristicLengthFromCurvature = 0;
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