[Gmsh] Uniform element size throughout the geometry

Harris FAROOQ harris.farooq at mines-paristech.fr
Thu May 17 10:27:58 CEST 2018


Hello, 

With the default algorithm we get coarse elements away from the element set boundary. 

By default algorithm I mean: gmsh file.geo -3 

Best regards, 
Harris 
----- Original Message -----

From: "Christophe Geuzaine" <geuzaine at gmail.com> 
To: "Harris FAROOQ" <harris.farooq at mines-paristech.fr> 
Cc: gmsh at onelab.info 
Sent: Thursday, May 17, 2018 8:55:15 AM 
Subject: Re: [Gmsh] Uniform element size throughout the geometry 


With the default algorithm evrything looks ok to me (don't use -algo front3d unless you really have to). 




On 9 May 2018, at 17:12, Harris FAROOQ < harris.farooq at mines-paristech.fr > wrote: 

Hello, 

I am trying to get a uniform element size throughout the geometry. I have tried giving a constant value to element size and mesh "mesh size fields" but they do not work i.e. I get a uniform mesh at the boundary but inside the geometry, the elements are coarse. 

I have also attached an image to clarify the problem. 

I have also tried: 
-algo front3d -3

or

-algo front3d -3 -optimize_netgen 
but these options do not give a uniform mesh inside the geometry. 

Is it possible to get a uniform mesh size throughout the geometry? 

My geo file looks like this: 

Point(1) ={0.315650761382760, 0.894382926819093, -0.302448630706616, 0.100000000000000}; 
Point(2) ={1.298440033476073, 1.362940371711625, 0.283099223758606, 0.100000000000000}; 
Point(3) ={1.298440033476073, 0.894382926819093, -0.262655810088256, 0.100000000000000}; 
Point(4) ={0.735232865266709, 1.411647357936784, 0.283099223758606, 0.100000000000000}; 
Point(5) ={0.340187717154710, 1.411647357936784, 0.311264675576753, 0.100000000000000}; 
Point(6) ={0.298440033476073, 0.457103015216639, 0.283099223758606, 0.100000000000000}; 
Point(7) ={0.903394885364074, 0.894382926819093, 0.697551369293384, 0.100000000000000}; 
Point(8) ={1.298440033476073, 0.894382926819093, 0.669385917475237, 0.100000000000000}; 
Point(9) ={0.340187717154710, 0.848927269539238, 0.697551369293384, 0.100000000000000}; 
Point(10) ={0.340187717154709, 0.411647357936784, 0.243306403140246, 0.100000000000000}; 
Point(11) ={0.735232865266709, 0.411647357936784, 0.283099223758606, 0.100000000000000}; 
Point(12) ={1.298440033476073, 0.457103015216640, 0.283099223758606, 0.100000000000000}; 
Point(13) ={0.903394885364074, 0.894382926819093, -0.302448630706616, 0.100000000000000}; 
Point(14) ={0.298440033476073, 0.894382926819093, -0.262655810088257, 0.100000000000000}; 
Point(15) ={0.322976989248022, 1.411647357936784, 0.283099223758606, 0.100000000000000}; 
Point(16) ={0.340187717154710, 0.943089913044252, 0.697551369293384, 0.100000000000000}; 
Point(17) ={0.315650761382760, 0.894382926819093, 0.697551369293384, 0.100000000000000}; 
Point(18) ={0.340187717154709, 0.848927269539238, -0.302448630706616, 0.100000000000000}; 
Point(19) ={0.322976989248022, 0.411647357936784, 0.283099223758606, 0.100000000000000}; 
Point(20) ={0.340187717154710, 0.411647357936784, 0.311264675576753, 0.100000000000000}; 
Point(21) ={0.340187717154709, 1.411647357936784, 0.243306403140246, 0.100000000000000}; 
Point(22) ={0.340187717154709, 0.943089913044252, -0.302448630706616, 0.100000000000000}; 
Point(23) ={0.298440033476073, 1.362940371711625, 0.283099223758606, 0.100000000000000}; 
Point(24) ={0.298440033476073, 0.894382926819093, 0.669385917475237, 0.100000000000000}; 
Point(25) ={0.340187717154710, -0.056910086955748, 0.697551369293384, 0.100000000000000}; 
Point(26) ={0.903394885364075, -0.105617073180907, 0.697551369293384, 0.100000000000000}; 
Point(27) ={1.322976989248022, 0.411647357936784, 1.283099223758606, 0.100000000000000}; 
Point(28) ={1.298440033476073, 0.362940371711625, 1.283099223758606, 0.100000000000000}; 
Point(29) ={0.340187717154710, 0.411647357936784, 1.243306403140246, 0.100000000000000}; 
Point(30) ={1.298440033476073, 0.457103015216639, 1.283099223758606, 0.100000000000000}; 
Point(31) ={1.340187717154710, -0.056910086955748, 0.697551369293384, 0.100000000000000}; 
Point(32) ={1.315650761382761, 0.894382926819093, 0.697551369293384, 0.100000000000000}; 
Point(33) ={0.735232865266709, 0.411647357936784, 1.283099223758606, 0.100000000000000}; 
Point(34) ={1.298440033476073, 0.894382926819093, 0.737344189911744, 0.100000000000000}; 
Point(35) ={1.298440033476074, -0.105617073180907, 0.737344189911744, 0.100000000000000}; 
Point(36) ={1.298440033476073, 0.362940371711625, 0.283099223758606, 0.100000000000000}; 
Point(37) ={1.315650761382761, -0.105617073180907, 0.697551369293384, 0.100000000000000}; 
Point(38) ={1.298440033476073, -0.105617073180907, 0.669385917475237, 0.100000000000000}; 
Point(39) ={1.340187717154710, 0.411647357936784, 1.243306403140246, 0.100000000000000}; 
Point(40) ={1.322976989248022, 0.411647357936784, 0.283099223758606, 0.100000000000000}; 
Point(41) ={1.340187717154710, 0.848927269539238, 0.697551369293384, 0.100000000000000}; 
Point(42) ={1.340187717154710, 0.411647357936784, 0.311264675576753, 0.100000000000000}; 
Line(1) = {2, 3}; 
Line(2) = {3, 12}; 
Line(3) = {12, 8}; 
Line(4) = {8, 2}; 
Line(5) = {2, 4}; 
Line(6) = {4, 21}; 
Line(7) = {21, 22}; 
Line(8) = {22, 13}; 
Line(9) = {13, 3}; 
Line(10) = {8, 7}; 
Line(11) = {7, 16}; 
Line(12) = {16, 5}; 
Line(13) = {5, 4}; 
Line(14) = {13, 18}; 
Line(15) = {18, 10}; 
Line(16) = {10, 11}; 
Line(17) = {11, 12}; 
Line(18) = {5, 15}; 
Line(19) = {15, 21}; 
Line(20) = {16, 17}; 
Line(21) = {17, 24}; 
Line(22) = {24, 23}; 
Line(23) = {23, 15}; 
Line(24) = {6, 24}; 
Line(25) = {17, 9}; 
Line(26) = {9, 20}; 
Line(27) = {20, 19}; 
Line(28) = {19, 6}; 
Line(29) = {6, 14}; 
Line(30) = {14, 23}; 
Line(31) = {19, 10}; 
Line(32) = {18, 1}; 
Line(33) = {1, 14}; 
Line(34) = {7, 9}; 
Line(35) = {11, 20}; 
Line(36) = {22, 1}; 
Line(37) = {26, 35}; 
Line(38) = {35, 37}; 
Line(39) = {37, 38}; 
Line(40) = {38, 26}; 
Line(41) = {26, 25}; 
Line(42) = {25, 29}; 
Line(43) = {29, 33}; 
Line(44) = {33, 28}; 
Line(45) = {28, 35}; 
Line(46) = {38, 36}; 
Line(47) = {36, 11}; 
Line(48) = {20, 25}; 
Line(49) = {27, 30}; 
Line(50) = {30, 34}; 
Line(51) = {34, 32}; 
Line(52) = {32, 41}; 
Line(53) = {41, 39}; 
Line(54) = {39, 27}; 
Line(55) = {27, 28}; 
Line(56) = {33, 30}; 
Line(57) = {39, 31}; 
Line(58) = {31, 37}; 
Line(59) = {36, 40}; 
Line(60) = {40, 12}; 
Line(61) = {40, 42}; 
Line(62) = {42, 41}; 
Line(63) = {32, 8}; 
Line(64) = {34, 7}; 
Line(65) = {9, 29}; 
Line(66) = {31, 42}; 
Line Loop(67) = {1, 2, 3, 4}; 
Plane Surface(1) = {67}; 
Line Loop(68) = {5, 6, 7, 8, 9, -1}; 
Plane Surface(2) = {68}; 
Line Loop(69) = {-4, 10, 11, 12, 13, -5}; 
Plane Surface(3) = {69}; 
Line Loop(70) = {-9, 14, 15, 16, 17, -2}; 
Plane Surface(4) = {70}; 
Line Loop(71) = {-13, 18, 19, -6}; 
Plane Surface(5) = {71}; 
Line Loop(72) = {-12, 20, 21, 22, 23, -18}; 
Plane Surface(6) = {72}; 
Line Loop(73) = {24, -21, 25, 26, 27, 28}; 
Plane Surface(7) = {73}; 
Line Loop(74) = {29, 30, -22, -24}; 
Plane Surface(8) = {74}; 
Line Loop(75) = {-28, 31, -15, 32, 33, -29}; 
Plane Surface(9) = {75}; 
Line Loop(76) = {34, -25, -20, -11}; 
Plane Surface(10) = {76}; 
Line Loop(77) = {-10, -3, -17, 35, -26, -34}; 
Plane Surface(11) = {77}; 
Line Loop(78) = {-31, -27, -35, -16}; 
Plane Surface(12) = {78}; 
Line Loop(79) = {-8, 36, -32, -14}; 
Plane Surface(13) = {79}; 
Line Loop(80) = {-33, -36, -7, -19, -23, -30}; 
Plane Surface(14) = {80}; 
Line Loop(81) = {37, 38, 39, 40}; 
Plane Surface(15) = {81}; 
Line Loop(82) = {41, 42, 43, 44, 45, -37}; 
Plane Surface(16) = {82}; 
Line Loop(83) = {-40, 46, 47, 35, 48, -41}; 
Plane Surface(17) = {83}; 
Line Loop(84) = {49, 50, 51, 52, 53, 54}; 
Plane Surface(18) = {84}; 
Line Loop(85) = {55, -44, 56, -49}; 
Plane Surface(19) = {85}; 
Line Loop(86) = {-54, 57, 58, -38, -45, -55}; 
Plane Surface(20) = {86}; 
Line Loop(87) = {-47, 59, 60, -17}; 
Plane Surface(21) = {87}; 
Line Loop(88) = {-3, -60, 61, 62, -52, 63}; 
Plane Surface(22) = {88}; 
Line Loop(89) = {-63, -51, 64, -10}; 
Plane Surface(23) = {89}; 
Line Loop(90) = {-42, -48, -26, 65}; 
Plane Surface(24) = {90}; 
Line Loop(91) = {-65, -34, -64, -50, -56, -43}; 
Plane Surface(25) = {91}; 
Line Loop(92) = {66, -61, -59, -46, -39, -58}; 
Plane Surface(26) = {92}; 
Line Loop(93) = {-57, -53, -62, -66}; 
Plane Surface(27) = {93}; 
Surface Loop(29) = {1,2,3,4,5,6,7,8,9,10,11,12,13,14}; 
Volume(1)={29}; 
Physical Volume(1)={1}; 
Surface Loop(30) = {15,16,17,18,19,20,11,21,22,23,24,25,26,27}; 
Volume(2)={30}; 
Physical Volume(2)={2}; 
Periodic Surface 1 {1,2,3,4} = 8 {-30,-29,24,22}; 
Periodic Surface 2 {5,6,7,8,9,-1} = 3 {5,-13,-12,-11,-10,4}; 
Periodic Surface 2 {5,6,7,8,9,-1} = 4 {-17,-16,-15,-14,9,2}; 
Periodic Surface 2 {5,6,7,8,9,-1} = 14 {23,19,7,36,33,30}; 
Periodic Surface 3 {-4,10,11,12,13,-5} = 6 {-22,-21,-20,12,18,-23}; 
Periodic Surface 3 {-4,10,11,12,13,-5} = 11 {3,10,34,26,-35,17}; 
Periodic Surface 3 {-4,10,11,12,13,-5} = 17 {-46,40,41,-48,-35,-47}; 
Periodic Surface 4 {-9,14,15,16,17,-2} = 9 {-33,-32,15,-31,28,29}; 
Periodic Surface 4 {-9,14,15,16,17,-2} = 11 {10,34,26,-35,17,3}; 
Periodic Surface 4 {-9,14,15,16,17,-2} = 25 {64,34,65,43,56,50}; 
Periodic Surface 5 {-13,18,19,-6} = 12 {35,27,31,16}; 
Periodic Surface 6 {-12,20,21,22,23,-18} = 7 {-26,-25,21,-24,-28,-27}; 
Periodic Surface 6 {-12,20,21,22,23,-18} = 14 {7,36,33,30,23,19}; 
Periodic Surface 7 {24,-21,25,26,27,28} = 9 {29,-33,-32,15,-31,28}; 
Periodic Surface 7 {24,-21,25,26,27,28} = 11 {3,10,34,26,-35,17}; 
Periodic Surface 7 {24,-21,25,26,27,28} = 22 {3,-63,52,-62,-61,60}; 
Periodic Surface 9 {-28,31,-15,32,33,-29} = 14 {23,19,7,36,33,30}; 
Periodic Surface 10 {34,-25,-20,-11} = 13 {14,32,-36,8}; 
Periodic Surface 11 {-10,-3,-17,35,-26,-34} = 17 {40,-46,-47,-35,-48,41}; 
Periodic Surface 11 {-10,-3,-17,35,-26,-34} = 22 {-63,3,60,-61,-62,52}; 
Periodic Surface 11 {-10,-3,-17,35,-26,-34} = 25 {64,50,56,43,65,34}; 
Periodic Surface 15 {37,38,39,40} = 23 {-64,51,63,10}; 
Periodic Surface 16 {41,42,43,44,45,-37} = 17 {41,-48,-35,-47,-46,40}; 
Periodic Surface 16 {41,42,43,44,45,-37} = 20 {-58,-57,54,55,45,38}; 
Periodic Surface 16 {41,42,43,44,45,-37} = 25 {34,65,43,56,50,64}; 
Periodic Surface 17 {-40,46,47,35,48,-41} = 26 {39,46,59,61,-66,58}; 
Periodic Surface 18 {49,50,51,52,53,54} = 20 {55,45,38,-58,-57,54}; 
Periodic Surface 18 {49,50,51,52,53,54} = 22 {60,3,-63,52,-62,-61}; 
Periodic Surface 18 {49,50,51,52,53,54} = 25 {56,50,64,34,65,43}; 
Periodic Surface 19 {55,-44,56,-49} = 21 {-59,47,17,-60}; 
Periodic Surface 20 {-54,57,58,-38,-45,-55} = 26 {61,-66,58,39,46,59}; 
Periodic Surface 22 {-3,-60,61,62,-52,63} = 26 {46,59,61,-66,58,39}; 
Periodic Surface 24 {-42,-48,-26,65} = 27 {57,66,62,53}; 


Best regards, 
Harris Farooq 
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