[Gmsh] Problem with the Boolean Operation
Christophe Geuzaine
cgeuzaine at uliege.be
Thu Jul 26 17:32:43 CEST 2018
Dear all,
Just to confirm that currently we don't try to be "too intelligent" about mesh size constraints after boolean operations: if new geometrical points are created (at new locations), we do not try to guess a mesh size constraint at these points. So they get assigned the default ("infinity") size.
If mesh size constraints are associated to other points, we could do some interpolation - but the question then arises as to which is the most natural way. Any suggestions are welcome: the best would be to create an issue in our gitlab and add your ideas there.
Christophe
> On 17 Jul 2018, at 16:47, Matthieu Lecouvez <matthieu.lecouvez at gmail.com> wrote:
>
> Hi all,
>
> I have never managed to figure out how GMSH keeps track of the mesh sizes during boolean operations. The solution I came up with is to set the mesh sizes after the operation : Say you have two surfaces (with id 1 and 2) sharing a common interface and you want to set a mesh size h1 on surface 1, and h2 on surface 2, with h1 > h2, then :
>
> - out[] = PointsOf { Surface{1}; };
> - Characteristic Length {out[]} = h1;
> - out[] = PointsOf { Surface{2}; };
> - Characteristic Length {out[]} = h2;
>
> Note that the order in which you set the mesh sizes does matter, you probably want to set the smallest mesh sizes last.
> Also, you need to do that only for your surfaces that have been modified by the boolean operation.
>
> Hope this helps.
>
> Matt
>
>
> 2018-07-17 15:41 GMT+02:00 Benoit CURVERS <benoit.curvers at screen-lasse.com <mailto:benoit.curvers at screen-lasse.com>>:
> Hello Juan,
>
> Thank you very much for your answer.
> I already tried the solution you gave me. I tried to add a specific box in order to refine the mesh in specific part but unfortunately, I did not obtain the result I wanted
> As a result, this solution is not suitable for my problem (in 2D and 3D case)
>
> So, I just would like to know : how does GMSH keep the mesh size on the points after a Boolean operation ? Does GMSH chose the size randomly ? Does GMSH chose the size thank to the points' index ?
>
> Thank you very much for your answer,
> Kind regards,
>
> Benoît CURVERS
> Laser Systems & Solutions of Europe (LASSE)
> SCREEN Semiconductor Solutions Co. Ltd
> Taïwan Cell : +886 (0)965-875-974 or 7629511
> Email : benoit.curvers at screen-lasse.com <mailto:benoit.curvers at screen-lasse.com>
>
>
>
> -----Message d'origine-----
> De : gmsh <gmsh-bounces at ace20.montefiore.ulg.ac.be <mailto:gmsh-bounces at ace20.montefiore.ulg.ac.be>> De la part de Juan E. Sanchez
> Envoyé : vendredi 13 juillet 2018 17:51
> À : gmsh at onelab.info <mailto:gmsh at onelab.info>
> Objet : Re: [Gmsh] Problem with the Boolean Operation
>
> Hi Benoit,
>
> I recommend a background field. Here is a project where I did some refinement (based on electric field) for a semiconductor simulation.
>
> https://github.com/devsim/devsim_bjt_example <https://github.com/devsim/devsim_bjt_example>
>
> All the simulation files are there, as well as a book chapter in pdf form.
>
> At that time of the work, the boolean operations were not available in gmsh.
>
> Regards,
>
> Juan
>
>
> On 7/12/18 9:56 AM, Benoit CURVERS wrote:
> > Dear,
> >
> > I am writing in connection with the Boolean operation with GMSH. I
> > have some trouble with the meshing size on points after a Boolean operation.
> >
> > For example, on the picture below, I have four main surface. In the
> > geo file, I create my surface according to the mesh size.
> >
> > So, first, I create the surface 6 and 8 with the mesh size of 1 and
> > after the layer 3 and 5 with the mesh size of 10.
> >
> > But when I perform the Boolean operation (Boolean fragment), in one
> > case, the minimal size is keeping and in the other case, the maximal
> > size is keeping (as you can see with the red circle).
> >
> > So, I would like to know, How does GMSH keep the size after a Boolean
> > operation ? Is there a specific condition or GMSH chose the size randomly ?
> >
> > Because it seems that the size is not chosen according to the index,
> > or to the creation's order or to the mesh size
> >
> > I also see this problem in 3D.
> >
> > You can find the geo file below.
> >
> > Thank you for your answer,
> >
> > Kind regards,
> >
> > Benoît CURVERS
> >
> > *Laser Systems & Solutions of Europe (LASSE)*
> >
> > SCREEN Semiconductor Solutions Co. Ltd
> >
> > Taïwan Cell : +886 (0)965-875-974 or 7629511
> >
> > Email : benoit.curvers at screen-lasse.com <mailto:benoit.curvers at screen-lasse.com>
> > <mailto:benoit.curvers at screen-lasse.com <mailto:benoit.curvers at screen-lasse.com>>
> >
> > SetFactory("OpenCASCADE");
> >
> > // TopFin
> >
> > p10=newp; Point(p10) = {-2.5,60,0, 0.5};
> >
> > p11=newp; Point(p11) = {-2.5,22.5,0, 0.5};
> >
> > p12=newp; Point(p12) = {-1.75,20.5,0, 0.5};
> >
> > p13=newp; Point(p13) = {-1,20,0, 0.5};
> >
> > p14=newp; Point(p14) = {1,20,0, 0.5};
> >
> > p15=newp; Point(p15) = {1.75,20.5,0, 0.5};
> >
> > p16=newp; Point(p16) = {2.5,22.5,0, 0.5};
> >
> > p17=newp; Point(p17) = {2.5,60,0, 0.5};
> >
> > l10=newl; Line(l10) = {p10,p11};
> >
> > l11=newl; Line(l11) = {p11,p12};
> >
> > l12=newl; Line(l12) = {p12,p13};
> >
> > l13=newl; Line(l13) = {p13,p14};
> >
> > l14=newl; Line(l14) = {p14,p15};
> >
> > l15=newl; Line(l15) = {p15,p16};
> >
> > l16=newl; Line(l16) = {p16,p17};
> >
> > l17=newl; Line(l17) = {p17,p10};
> >
> > ll10 = newll; Line Loop(ll10) = {l10,l11,l12,l13,l14,l15,l16,l17};
> >
> > Plane Surface(1) = {ll10};
> >
> > Physical Surface(1)={1};
> >
> > // Bot1
> >
> > p20=newp; Point(p20) = {-15.235,120,0, 0.5};
> >
> > p21=newp; Point(p21) = {-13,119.3,0, 0.5};
> >
> > p22=newp; Point(p22) = {-12,119,0, 0.5};
> >
> > p23=newp; Point(p23) = {-10.9,118.1,0, 0.5};
> >
> > p24=newp; Point(p24) = {-10,117,0, 0.5};
> >
> > p25=newp; Point(p25) = {-9.7,116,0, 0.5};
> >
> > p26=newp; Point(p26) = {-9.235,114,0, 0.5};
> >
> > p27=newp; Point(p27) = {-10,120,0, 0.5};
> >
> > l20=newl; Line(l20) = {p20,p21};
> >
> > l21=newl; Line(l21) = {p21,p22};
> >
> > l22=newl; Line(l22) = {p22,p23};
> >
> > l23=newl; Line(l23) = {p23,p24};
> >
> > l24=newl; Line(l24) = {p24,p25};
> >
> > l25=newl; Line(l25) = {p25,p26};
> >
> > l26=newl; Line(l26) = {p26,p27};
> >
> > l27=newl; Line(l27) = {p27,p20};
> >
> > ll20 = newll; Line Loop(ll20) = {l20,l21,l22,l23,l24,l25,l26,l27};
> >
> > Plane Surface(2) = {ll20};
> >
> > Physical Surface(2)={2};
> >
> > // Bot2
> >
> > p40=newp; Point(p40) = {10,120,0, 0.5};
> >
> > p41=newp; Point(p41) = {9.235,114,0, 0.5};
> >
> > p42=newp; Point(p42) = {9.7,116,0, 0.5};
> >
> > p43=newp; Point(p43) = {10,117,0, 0.5};
> >
> > p44=newp; Point(p44) = {10.9,118.1,0, 0.5};
> >
> > p45=newp; Point(p45) = {12,119,0, 0.5};
> >
> > p46=newp; Point(p46) = {13,119.3,0, 0.5};
> >
> > p47=newp; Point(p47) = {15.235,120,0, 0.5};
> >
> > l40=newl; Line(l40) = {p40,p41};
> >
> > l41=newl; Line(l41) = {p41,p42};
> >
> > l42=newl; Line(l42) = {p42,p43};
> >
> > l43=newl; Line(l43) = {p43,p44};
> >
> > l44=newl; Line(l44) = {p44,p45};
> >
> > l45=newl; Line(l45) = {p45,p46};
> >
> > l46=newl; Line(l46) = {p46,p47};
> >
> > l47=newl; Line(l47) = {p47,p40};
> >
> > ll40 = newll; Line Loop(ll40) = {l40,l41,l42,l43,l44,l45,l46,l47};
> >
> > Plane Surface(4) = {ll40};
> >
> > Physical Surface(4)={4};
> >
> > // BotFin
> >
> > p60=newp; Point(p60) = {-10,120,0, 0.5};
> >
> > p61=newp; Point(p61) = {-9.235,114,0, 0.5};
> >
> > p62=newp; Point(p62) = {-2.5,60,0, 0.5};
> >
> > p63=newp; Point(p63) = {2.5,60,0, 0.5};
> >
> > p64=newp; Point(p64) = {9.235,114,0, 0.5};
> >
> > p65=newp; Point(p65) = {10,120,0, 0.5};
> >
> > l60=newl; Line(l60) = {p60,p61};
> >
> > l61=newl; Line(l61) = {p61,p62};
> >
> > l62=newl; Line(l62) = {p62,p63};
> >
> > l63=newl; Line(l63) = {p63,p64};
> >
> > l64=newl; Line(l64) = {p64,p65};
> >
> > l65=newl; Line(l65) = {p65,p60};
> >
> > ll60 = newll; Line Loop(ll60) = {l60,l61,l62,l63,l64,l65};
> >
> > Plane Surface(6) = {ll60};
> >
> > Physical Surface(6)={6};
> >
> > // Substrate
> >
> > p80=newp; Point(p80) = {-67.5,120,0, 1};
> >
> > p81=newp; Point(p81) = {-15.235,120,0, 1};
> >
> > p82=newp; Point(p82) = {-10,120,0, 1};
> >
> > p83=newp; Point(p83) = {10,120,0, 1};
> >
> > p84=newp; Point(p84) = {15.235,120,0, 1};
> >
> > p85=newp; Point(p85) = {67.5,120,0, 1};
> >
> > p86=newp; Point(p86) = {67.5,140,0, 1};
> >
> > p87=newp; Point(p87) = {-67.5,140,0, 1};
> >
> > l80=newl; Line(l80) = {p80,p81};
> >
> > l81=newl; Line(l81) = {p81,p82};
> >
> > l82=newl; Line(l82) = {p82,p83};
> >
> > l83=newl; Line(l83) = {p83,p84};
> >
> > l84=newl; Line(l84) = {p84,p85};
> >
> > l85=newl; Line(l85) = {p85,p86};
> >
> > l86=newl; Line(l86) = {p86,p87};
> >
> > l87=newl; Line(l87) = {p87,p80};
> >
> > ll80 = newll; Line Loop(ll80) = {l80,l81,l82,l83,l84,l85,l86,l87};
> >
> > Plane Surface(8) = {ll80};
> >
> > Physical Surface(8)={8};
> >
> > // Ins
> >
> > p90=newp; Point(p90) = {-3.5,60,0, 1};
> >
> > p91=newp; Point(p91) = {-3.5,22.5,0, 1};
> >
> > p92=newp; Point(p92) = {-2.75,20,0, 1};
> >
> > p93=newp; Point(p93) = {-1,19,0, 1};
> >
> > p94=newp; Point(p94) = {1,19,0, 1};
> >
> > p95=newp; Point(p95) = {2.75,20,0, 1};
> >
> > p96=newp; Point(p96) = {3.5,22.5,0, 1};
> >
> > p97=newp; Point(p97) = {3.5,60,0, 1};
> >
> > p98=newp; Point(p98) = {2.5,60,0, 1};
> >
> > p99=newp; Point(p99) = {2.5,22.5,0, 1};
> >
> > p910=newp; Point(p910) = {1.75,20.5,0, 1};
> >
> > p911=newp; Point(p911) = {1,20,0, 1};
> >
> > p912=newp; Point(p912) = {-1,20,0, 1};
> >
> > p913=newp; Point(p913) = {-1.75,20.5,0, 1};
> >
> > p914=newp; Point(p914) = {-2.5,22.5,0, 1};
> >
> > p915=newp; Point(p915) = {-2.5,60,0, 1};
> >
> > l90=newl; Line(l90) = {p90,p91};
> >
> > l91=newl; Line(l91) = {p91,p92};
> >
> > l92=newl; Line(l92) = {p92,p93};
> >
> > l93=newl; Line(l93) = {p93,p94};
> >
> > l94=newl; Line(l94) = {p94,p95};
> >
> > l95=newl; Line(l95) = {p95,p96};
> >
> > l96=newl; Line(l96) = {p96,p97};
> >
> > l97=newl; Line(l97) = {p97,p98};
> >
> > l98=newl; Line(l98) = {p98,p99};
> >
> > l99=newl; Line(l99) = {p99,p910};
> >
> > l910=newl; Line(l910) = {p910,p911};
> >
> > l911=newl; Line(l911) = {p911,p912};
> >
> > l912=newl; Line(l912) = {p912,p913};
> >
> > l913=newl; Line(l913) = {p913,p914};
> >
> > l914=newl; Line(l914) = {p914,p915};
> >
> > l915=newl; Line(l915) = {p915,p90};
> >
> > ll90 = newll; Line Loop(ll90) =
> > {l90,l91,l92,l93,l94,l95,l96,l97,l98,l99,l910,l911,l912,l913,l914,l915
> > };
> >
> > Plane Surface(9) = {ll90};
> >
> > Physical Surface(9)={9};
> >
> > // Ox1
> >
> > p30=newp; Point(p30) = {-67.5,120,0, 10};
> >
> > p31=newp; Point(p31) = {-67.5,60,0, 10};
> >
> > p32=newp; Point(p32) = {-3.5,60,0, 10};
> >
> > p33=newp; Point(p33) = {-2.5,60,0, 10};
> >
> > p34=newp; Point(p34) = {-9.235,114,0, 10};
> >
> > p35=newp; Point(p35) = {-9.7,116,0, 10};
> >
> > p36=newp; Point(p36) = {-10,117,0, 10};
> >
> > p37=newp; Point(p37) = {-10.9,118.1,0, 10};
> >
> > p38=newp; Point(p38) = {-12,119,0, 10};
> >
> > p39=newp; Point(p39) = {-13,119.3,0, 10};
> >
> > p310=newp; Point(p310) = {-15.235,120,0, 10};
> >
> > l30=newl; Line(l30) = {p30,p31};
> >
> > l31=newl; Line(l31) = {p31,p32};
> >
> > l32=newl; Line(l32) = {p32,p33};
> >
> > l33=newl; Line(l33) = {p33,p34};
> >
> > l34=newl; Line(l34) = {p34,p35};
> >
> > l35=newl; Line(l35) = {p35,p36};
> >
> > l36=newl; Line(l36) = {p36,p37};
> >
> > l37=newl; Line(l37) = {p37,p38};
> >
> > l38=newl; Line(l38) = {p38,p39};
> >
> > l39=newl; Line(l39) = {p39,p310};
> >
> > l310=newl; Line(l310) = {p310,p30};
> >
> > ll30 = newll; Line Loop(ll30) =
> > {l30,l31,l32,l33,l34,l35,l36,l37,l38,l39,l310};
> >
> > Plane Surface(3) = {ll30};
> >
> > Physical Surface(3)={3};
> >
> > // Ox2
> >
> > p50=newp; Point(p50) = {15.235,120,0, 10};
> >
> > p51=newp; Point(p51) = {13,119.3,0, 10};
> >
> > p52=newp; Point(p52) = {12,119,0, 10};
> >
> > p53=newp; Point(p53) = {10.9,118.1,0, 10};
> >
> > p54=newp; Point(p54) = {10,117,0, 10};
> >
> > p55=newp; Point(p55) = {9.7,116,0, 10};
> >
> > p56=newp; Point(p56) = {9.235,114,0, 10};
> >
> > p57=newp; Point(p57) = {2.5,60,0, 10};
> >
> > p58=newp; Point(p58) = {3.5,60,0, 10};
> >
> > p59=newp; Point(p59) = {67.5,60,0, 10};
> >
> > p510=newp; Point(p510) = {67.5,120,0, 10};
> >
> > l50=newl; Line(l50) = {p50,p51};
> >
> > l51=newl; Line(l51) = {p51,p52};
> >
> > l52=newl; Line(l52) = {p52,p53};
> >
> > l53=newl; Line(l53) = {p53,p54};
> >
> > l54=newl; Line(l54) = {p54,p55};
> >
> > l55=newl; Line(l55) = {p55,p56};
> >
> > l56=newl; Line(l56) = {p56,p57};
> >
> > l57=newl; Line(l57) = {p57,p58};
> >
> > l58=newl; Line(l58) = {p58,p59};
> >
> > l59=newl; Line(l59) = {p59,p510};
> >
> > l510=newl; Line(l510) = {p510,p50};
> >
> > ll50 = newll; Line Loop(ll50) =
> > {l50,l51,l52,l53,l54,l55,l56,l57,l58,l59,l510};
> >
> > Plane Surface(5) = {ll50};
> >
> > Physical Surface(5)={5};
> >
> > // Cap
> >
> > p70=newp; Point(p70) = {-67.5,60,0, 10};
> >
> > p71=newp; Point(p71) = {-67.5,10,0, 10};
> >
> > p72=newp; Point(p72) = {67.5,10,0, 10};
> >
> > p73=newp; Point(p73) = {67.5,60,0, 10};
> >
> > p74=newp; Point(p74) = {3.5,60,0, 10};
> >
> > p75=newp; Point(p75) = {3.5,22.5,0, 10};
> >
> > p76=newp; Point(p76) = {2.75,20,0, 10};
> >
> > p77=newp; Point(p77) = {1,19,0, 10};
> >
> > p78=newp; Point(p78) = {-1,19,0, 10};
> >
> > p79=newp; Point(p79) = {-2.75,20,0, 10};
> >
> > p710=newp; Point(p710) = {-3.5,22.5,0, 10};
> >
> > p711=newp; Point(p711) = {-3.5,60,0, 10};
> >
> > l70=newl; Line(l70) = {p70,p71};
> >
> > l71=newl; Line(l71) = {p71,p72};
> >
> > l72=newl; Line(l72) = {p72,p73};
> >
> > l73=newl; Line(l73) = {p73,p74};
> >
> > l74=newl; Line(l74) = {p74,p75};
> >
> > l75=newl; Line(l75) = {p75,p76};
> >
> > l76=newl; Line(l76) = {p76,p77};
> >
> > l77=newl; Line(l77) = {p77,p78};
> >
> > l78=newl; Line(l78) = {p78,p79};
> >
> > l79=newl; Line(l79) = {p79,p710};
> >
> > l710=newl; Line(l710) = {p710,p711};
> >
> > l711=newl; Line(l711) = {p711,p70};
> >
> > ll70 = newll; Line Loop(ll70) =
> > {l70,l71,l72,l73,l74,l75,l76,l77,l78,l79,l710,l711};
> >
> > Plane Surface(7) = {ll70};
> >
> > Physical Surface(7)={7};
> >
> > // AddedSubstrate
> >
> > p100=newp; Point(p100) = {-67.5,140,0, 5};
> >
> > p101=newp; Point(p101) = {67.5,140,0, 5};
> >
> > p102=newp; Point(p102) = {67.5,2140,0, 5};
> >
> > p103=newp; Point(p103) = {-67.5,2140,0, 5};
> >
> > l100=newl; Line(l100) = {p100,p101};
> >
> > l101=newl; Line(l101) = {p101,p102};
> >
> > l102=newl; Line(l102) = {p102,p103};
> >
> > l103=newl; Line(l103) = {p103,p100};
> >
> > ll100 = newll; Line Loop(ll100) = {l100,l101,l102,l103};
> >
> > Plane Surface(10) = {ll100};
> >
> > Physical Surface(10)={10};
> >
> > // AddedSubstrate
> >
> > p110=newp; Point(p110) = {-67.5,2140,0, 10};
> >
> > p111=newp; Point(p111) = {67.5,2140,0, 10};
> >
> > p112=newp; Point(p112) = {67.5,3140,0, 10};
> >
> > p113=newp; Point(p113) = {-67.5,3140,0, 10};
> >
> > l110=newl; Line(l110) = {p110,p111};
> >
> > l111=newl; Line(l111) = {p111,p112};
> >
> > l112=newl; Line(l112) = {p112,p113};
> >
> > l113=newl; Line(l113) = {p113,p110};
> >
> > ll110 = newll; Line Loop(ll110) = {l110,l111,l112,l113};
> >
> > Plane Surface(11) = {ll110};
> >
> > Physical Surface(11)={11};
> >
> > // AddedSubstrate
> >
> > p120=newp; Point(p120) = {-67.5,3140,0, 20};
> >
> > p121=newp; Point(p121) = {67.5,3140,0, 20};
> >
> > p122=newp; Point(p122) = {67.5,5140,0, 20};
> >
> > p123=newp; Point(p123) = {-67.5,5140,0, 20};
> >
> > l120=newl; Line(l120) = {p120,p121};
> >
> > l121=newl; Line(l121) = {p121,p122};
> >
> > l122=newl; Line(l122) = {p122,p123};
> >
> > l123=newl; Line(l123) = {p123,p120};
> >
> > ll120 = newll; Line Loop(ll120) = {l120,l121,l122,l123};
> >
> > Plane Surface(12) = {ll120};
> >
> > Physical Surface(12)={12};
> >
> > pAir1=newp; Point(pAir1) = {-67.5,-190,0, 30};
> >
> > pAir2=newp; Point(pAir2) = {67.5,-190,0, 30};
> >
> > pAir3=newp; Point(pAir3) = {67.5,5140,0, 30};
> >
> > pAir4=newp; Point(pAir4) = {-67.5,5140,0, 30};
> >
> > lAir1=newl; Line(lAir1) = {pAir1,pAir2};
> >
> > lAir2=newl; Line(lAir2) = {pAir2,pAir3};
> >
> > lAir3=newl; Line(lAir3) = {pAir3,pAir4};
> >
> > lAir4=newl; Line(lAir4) = {pAir4,pAir1};
> >
> > llAir = newll; Line Loop(llAir) = {lAir1,lAir2,lAir3,lAir4};
> >
> > rsAir = news ; Plane Surface(rsAir) = {llAir};
> >
> > v() = BooleanFragments{ Surface{1:12}; Delete; }{ Surface{rsAir};
> > Delete; };
> >
> > Physical Surface(0)={13};
> >
> >
> >
> > This body part will be downloaded on demand.
> >
>
>
> _______________________________________________
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>
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>
> _______________________________________________
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—
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science
http://www.montefiore.ulg.ac.be/~geuzaine
Free software: http://gmsh.info | http://getdp.info | http://onelab.info
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