# Integrating Multiple Meshes
**URL:** https://community.freefem.org/t/integrating-multiple-meshes/2914
**Category:** General Discussion
**Created:** [January 29, 2024, 9:41am UTC](https://community.freefem.org/t/integrating-multiple-meshes/2914 "2024-01-29T09:41:29Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@YOuungLi](https://community.freefem.org/u/YOuungLi)
#### Post date: [January 29, 2024, 9:41am UTC](https://community.freefem.org/t/integrating-multiple-meshes/2914/1 "2024-01-29T09:41:29Z")
Dear All,
I’m encountering an error while attempting to combine multiple meshes, and I’m having trouble understanding why this error persists even after adjusting the orientation.
error : “Bug in mortar constrution : close to vertex 9
current line = 14
Assertion fail : (linkd[is] == -2)
line :380, in file …/femlib/fem.cpp”
Below is the code I’ve been using:
int a = 2;
int m = 10;
int SD = m;
int HC = m;
int Bar = m;
int bar = m;
int SC = m;
border C1(t=0, 1.5){x=3-2_t; y=0; label=99;};
border C2(t=0, 1){x=3; y=2_t-2; label=99;};
border C3(t=0, 1){x=3+(a/2)_(1-t); y=-2; label=99;};
border C4(t=0, 1){x=a_2; y=-2+a\*(1-t); label=99;};
border C5(t=0, 1.5){x=a_2+2_(1.5-t); y=0; label=99;};
border C6(t=0, 1){x=7; y=-2\*(1-t); label=99;};
border C7(t=0, 1){x=7+(a/2)_(1-t); y=-2; label=99;};
border C8(t=0, 1){x=a_4; y=-2+a\*(1-t); label=99;};
border C9(t=0, 1.5){x=8+2\*(1.5-t); y=0; label=99;};
border C10(t=0, 1){x=11; y=a\*(1-t); label=99;};
border C11(t=0, 1.5){x=11-a\*(1.5-t); y=a; label=99;};
border C12(t=0, 1){x=8; y=a+a\*(1-t); label=99;};
border C13(t=0, 1){x=8-(a/2)_(1-t); y=a_2; label=99;};
border C14(t=0, 1){x=7; y=4-a\*(1-t); label=99;};
border C15(t=0, 1.5){x=7-a\*(1.5-t); y=2; label=99;};
border C16(t=0, 1){x=4; y=a+a\*(1-t); label=99;};
border C17(t=0, 1){x=4-(a/2)_(1-t); y=a_2; label=99;};
border C18(t=0, 1){x=3; y=4-a\*(1-t); label=99;};
border C19(t=0, 1.5){x=3-2\*(1.5-t); y=2; label=99;};
border C20(t=0, 1){x=0; y=a-a\*(1-t); label=99;};
// Contact1
border C21(t=0, 0.5){x=-1_t; y=0; label=1;};
border C22(t=0,2){x=0; y=1_t; label=1;};
border C23(t=0, 0.5){x=-0.5+1_t; y=2; label=1;};
border C24(t=0, 2){x=-0.5; y=2-1_t; label=1;};
// Contact2
border C25(t=0, 0.5){x=3; y=-2-1_t; label=1;};
border C26(t=0, 1){x=3+1_t; y=-2.5; label=1;};
border C27(t=0, 0.5){x=4; y=-2.5+1_t; label=1;};
border C28(t=0, 1){x=3+1_t; y=-2; label=1;};
// Contact3
border C29(t=0, 0.5){x=3; y=4.5-1_t; label=1;};
border C30(t=0, 1){x=4-1_t; y=4; label=1;};
border C31(t=0, 0.5){x=4; y=4+1_t; label=1;};
border C32(t=0, 1){x=4-1_t; y=4.5; label=1;};
// Contact4
border C33(t=0, 0.5){x=7; y=-2-1_t; label=1;};
border C34(t=0, 1){x=7+1_t; y=-2.5; label=1;};
border C35(t=0, 0.5){x=8; y=-2.5+1_t; label=1;};
border C36(t=0, 1){x=7+1_t; y=-2; label=1;};
// Contact5
border C37(t=0, 0.5){x=11+1_t; y=0; label=1;};
border C38(t=0, 2){x=11.5; y=1_t; label=1;};
border C39(t=0, 0.5){x=11.5-1_t; y=2; label=1;};
border C40(t=0, 2){x=11; y=1_t; label=1;};
// Contact6
border C41(t=0, 0.5){x=7; y=4.5-1_t; label=1;};
border C42(t=0, 1){x=8-1_t; y=4; label=1;};
border C43(t=0, 0.5){x=8; y=4+1_t; label=1;};
border C44(t=0, 1){x=8-1_t; y=4.5; label=1;};
func Hallbar = C1(-Bar)+C2(-bar)+C3(-HC)+C4(-bar)+C5(-Bar)+C6(-bar)+C7(-HC)+C8(-bar)+C9(-Bar)+C10(-SD)+C11(-Bar)+C12(-bar)+C13(-HC)
+C14(-bar)+C15(-Bar)+C16(-bar)+C17(-HC)+C18(-bar)+C19(-Bar)+C20(-SD);
plot(Hallbar, dim=2, wait=1);
func Contacts = C21(-SC)+C22(SD)+C23(-SC)+C24(SD)+C25(SC)+C26(HC)+C27(SC)+C28(-HC)+C29(SC)+C30(-HC)+C31(SC)+C32(HC)
+C33(SC)+C34(HC)+C35(SC)+C36(-HC)+C37(SC)+C38(SD)+C39(SC)+C40(-SD)+C41(SC)+C42(-HC)+C43(SC)+C44(HC);
//#plot(Contacts, dim=2, wait=1);
mesh Th = buildmesh(Hallbar+Contacts);
plot(Th,wait=1);
Thank you in advance!
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### Author:  [@frederichecht](https://community.freefem.org/u/frederichecht)
#### Post date: [January 30, 2024, 5:50pm UTC](https://community.freefem.org/t/integrating-multiple-meshes/2914/2 "2024-01-30T17:50:49Z")
Remember all edge (border) are oriented and the domain must be a the left of the edge
and do not double the contact line.
the starting of cottection !!!
[bbbb.edp](https://community.freefem.org/uploads/short-url/4ZbUUbm0Zye2oXCm5FFKh8hXXC6.edp) (2.9 KB)
A remark,for this kind of mesh you can use the multi border syntaxe to build the mesh
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### Author:  [@AdityasOcean](https://community.freefem.org/u/AdityasOcean)
#### Post date: [October 21, 2024, 4:57am UTC](https://community.freefem.org/t/integrating-multiple-meshes/2914/3 "2024-10-21T04:57:22Z")
This advice saved my day. Thank you Prof. Hecht