Hello,
I am using Gmsh to produce mesh that is used afterwards with an other
program. Then, I need the normals to be well orientated in the 3D mesh.
With the file .geo attached to this mail and the last version (2.2.5),
Gmsh is returning 3D normals opposites to the 2D and surfaces normals.
How can I resolve this ?
Thanks for your help,
Gaelle Gibert
// essai.geo
// plaque subductante
// definition des quantites
coef = 1e3; // coefficient multiplicateur --> en kilometres
taille_maille = 15*coef;
taille_maille2 = 20*coef;
taille_maille3 = 5*coef;
// axe des z
zero = 0; //"niveau de la mer"
base_croute = -10*coef;
baselitho = -50*coef; // base de la lithosphere oceanique
baselitho_cont = -100*coef; // base de la lithosphere continentale
dessous = 1* (baselitho_cont + base_croute);
epaisseur_litho = base_croute - baselitho; // epaisseur de la lithosphere
oceanique, signe positif
epaisseur_litho_cont = zero - baselitho_cont; // epaisseur de la lithosphere
continentale, signe positif
centre = -200*coef; //centre du cercle de la zone de contact
rayon = -1*centre; //taille du rayon (nombre positif)
centre_bas = centre + base_croute;
// axe des y
devant = 0;
milieu = 10*coef;
derriere = 20*coef;
//axe des x
zonecontacth = 0*coef; // est fixe a base_croute le point en z=0
alpha = Acos ((rayon - epaisseur_litho_cont)/centre);
largeur_zonecontact = Tan(alpha)* (rayon - epaisseur_litho_cont); // calcul de
la largeur selon x de la zone de contact entre les deux plaques
zonecontactb = zonecontacth + largeur_zonecontact; // abcisse du point a la
base de la lithosphere
droite = 500*coef;
gamma = Atan (baselitho_cont/zonecontactb);
beta = Pi + ( (Pi/2) - gamma );
baselitho_arc = baselitho_cont + epaisseur_litho * Sin (beta); //selon z
// definition des points
Point (113) = {zonecontacth, derriere, baselitho, taille_maille2}; //
Point (114) = {droite, derriere, baselitho, taille_maille2}; //
Point (115) = {droite, derriere, base_croute, taille_maille}; //
Point (116) = {zonecontacth, derriere, base_croute, taille_maille}; //
Point (120) = {zonecontactb, derriere, dessous, taille_maille3}; //
Point (121) = {zonecontacth, milieu, baselitho, taille_maille2}; //
Point (122) = {droite, milieu, baselitho, taille_maille2}; //
Point (123) = {droite, milieu, base_croute, taille_maille}; //
Point (124) = {zonecontacth, milieu, base_croute, taille_maille}; //
Point (126) = {zonecontactb, milieu, dessous, taille_maille3}; //
Point (137) = {zonecontacth, milieu, centre_bas, taille_maille2}; //
Point (138) = {zonecontacth, derriere, centre_bas, taille_maille2}; //
// definition des lignes
Line (116) = {120, 113}; //
Line (117) = {113, 114}; //
Line (118) = {114, 115}; //
Line (119) = {115, 116}; //
Circle (120) = {116, 138, 120}; //
Line (126) = {126, 121}; //
Line (127) = {121, 122};//
Line (128) = {122, 123}; //
Line (129) = {123, 124}; //
Circle (130) = {124, 137, 126}; //
Line (132) = {126, 120}; //
Line (134) = {124,116}; //
Line (136) = {121, 113}; //
Line (138) = {123, 115}; //
Line (140) = {122, 114}; //
// definition des surfaces
Line Loop (108) = {-120,-119,-118,-117,-116}; Plane Surface
(108)={108};
Line Loop (109) = {126,127,128,129,130}; Plane Surface (109) =
{109};
Line Loop (111) = {116,-136,-126,132}; Ruled Surface (111) =
{111};
Line Loop (113) = {117,-140,-127,136}; Plane Surface (113) =
{113};
Line Loop (115) = {120,-132,-130,134}; Ruled Surface (115) =
{115};
Line Loop (117) = {119,-134,-129,138}; Plane Surface (117) =
{117};
Line Loop (119) = {118,-138,-128,140}; Plane Surface (119) =
{119};
// definition du volume
Surface Loop (3) = {108,109,111,113,115,117,119}; Volume (3) = {3};
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