# Hi I am trying to model a 2D Lug angle using Gmsh 4.6. How can I combine transfinite quad and regular full quad meshes in the following geo file?

I need transfinite mesh a small section of the bolt hole to insert a crack. However, The transfinite mesh and regular full quad mesh seem being incompatible and throwing errors. How can I combine transfinite quad and regular full quad meshes in the following geo file? I used the following meshing options:

1. Packing of parallelogram (experimental)
2. Simple ful quad recombination
3. Recombine all triangular meshes (checked)
4. subdivision algorithm (none) I require a transfinite mesh in Region 1 so that I can do J integrals.
// Gmsh project created on Wed Sep 02 17:32:13 2020
ri=19.05;
ro=3*ri;
w=2*ro;
b=200+ri;
lc1=20;
lc2=0.5;
lc3=2;

Point(1) = {0, 0, 0, lc1};
Point(2) = {b, 0, 0, lc1};
Point(3) = {b, w, 0, lc2};
Point(4) = {0, w, 0, lc1};
Point(5) = {b, ro, 0, lc1};

Line(1) = {1, 2};
//+
Line(2) = {1, 4};
//+

cx=b; // center of hole
cy=ro;
l1=cx-ri;
r1=cx+ri;

//+
Point(6) = {l1, cy, 0, lc3};
//+
Point(7) = {r1, cy, 0, lc3};
//+
ct=0.98480775301220805936674302458952;
st=0.17364817766693034885171662676931;
Point(8) = {cx-ri*st, cy+ri*ct, 0, lc2};
//+
Point(9) = {cx+ri*st, cy+ri*ct, 0, lc2};
//+
Circle(6) = {7, 5, 9};
Circle(7) = {9, 5, 8};
Circle(8) = {8, 5, 6};

Point(10) = {cx+ri*st, cy-ri*ct, 0, lc3};
Circle(5) = {6, 5, 10};
Circle(9) = {10, 5, 7};

/* Point(11) = {cx-ri*st, w, 0, lc2}; */
Point(11) = {cx-ro*st, w, 0, lc2};
Point(12) = {cx+ro*st, cy+ro*ct, 0, lc2};

Line(3) = {4, 11};
Circle(4) = {2, 5, 12};

Line(10) = {3, 11};
Circle(11) = {12, 5 ,3};

Line(12) = {8, 11};
Line(13) = {9, 12};

//+
Curve Loop(1) = {-12, -7, 13, 11, 10};
Plane Surface(1) = {1};

Transfinite Curve{7} = 15;
Transfinite Curve{10} = 8;
Transfinite Curve{11} = 8;

Transfinite Curve {12,13} = 60;

Transfinite Surface{1}={8, 9, 12, 11};
Recombine Surface{1};

Curve Loop(2) = {1, 4, -13, -6, -9, -5, -8, 12, -3, -2};
Plane Surface(2) = {2};


• There is not question in your question. What specifically are you trying to find out here? – Wolfgang Bangerth Sep 16 '20 at 21:30
• Hi. I am getting errors when I am combining tranfinite and regular meshes. How can I combine transfinite quad and regular full quad meshes in the above geo file? – CrimeFighterCE Sep 17 '20 at 5:16