[Gmsh] GMSH doesn’t want to make grid inside sphere
Andrey
spiritualworlds at mail.ru
Thu Jun 18 10:52:00 CEST 2009
Dear GMSH community!
Let’s consider the following geometry:
Input data to GMSH is a triangulated sphere of radius=1.
Each point of triangulation has constant characteristic length.
I pass triangulated sphere to GMSH in order to get meshed volume inside:
gmsh-win.exe -3 boundary.geo -o mesh.mesh -format mesh -order 1 -algo
iso -optimize
Then I consider two different cases (input geometry is the same, the
only difference is characteristic length):
1) If characteristic length=0.025 – everything is OK.
See attached input: boundary_good.zip and produced: sphere_good.png
Output of quality for this case:
Info : Opti : 0.00 < QUAL < 0.10 : 0 elements
Info : Opti : 0.10 < QUAL < 0.20 : 0 elements
Info : Opti : 0.20 < QUAL < 0.30 : 8 elements
Info : Opti : 0.30 < QUAL < 0.40 : 113 elements
Info : Opti : 0.40 < QUAL < 0.50 : 3134 elements
Info : Opti : 0.50 < QUAL < 0.60 : 112218 elements
Info : Opti : 0.60 < QUAL < 0.70 : 285051 elements
Info : Opti : 0.70 < QUAL < 0.80 : 389672 elements
Info : Opti : 0.80 < QUAL < 0.90 : 184604 elements
Info : Opti : 0.90 < QUAL < 1.00 : 15858 elements
2) If characteristic length=0.05 – produced mesh is not correct.
See attached input: boundary_bad.zip and produced: sphere_bad.png
Output of quality for this case:
Info : Opti : 0.00 < QUAL < 0.10 : 0 elements
Info : Opti : 0.10 < QUAL < 0.20 : 2707 elements
Info : Opti : 0.20 < QUAL < 0.30 : 2033 elements
Info : Opti : 0.30 < QUAL < 0.40 : 923 elements
Info : Opti : 0.40 < QUAL < 0.50 : 649 elements
Info : Opti : 0.50 < QUAL < 0.60 : 670 elements
Info : Opti : 0.60 < QUAL < 0.70 : 606 elements
Info : Opti : 0.70 < QUAL < 0.80 : 425 elements
Info : Opti : 0.80 < QUAL < 0.90 : 174 elements
Info : Opti : 0.90 < QUAL < 1.00 : 15 elements
Summary:
First case is more complex, because of larger amount of produced
tetrahedra and because 2D-frames (of input data) are also meshed by GMSH
(according to characteristic lengths). But first case is handled
correctly, the second - not.
Ant suggestions?
Best regards,
Andrey
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