dx = 1.0;dy = 1.0;dz = 5.0;nx = 20;ny = 20;nz = 1;cx = dx/nx;cy = dy/ny;cz = (cx + cy)/2;Point(1) = {0.0,0.0,0.0,1.0};Point(2) = {dx,0.0,0.0,1.0};Point(3) = {dx,dy,0.0,1.0};Point(4) = {0.0,dy,0.0,1.0};Line(1) = {1,2};Line(2) = {2,3};Line(3) = {3,4};Line(4) = {4,1};Line Loop(5) = {1,2,3,4};Plane Surface(6) = {5};//Transfinite Surface {6} = {1,4,3,2};//Recombine Surface {6};out[] = Extrude {0,0,dz} { Surface{6}; Layers { 1 }; Recombine; }; Transfinite Line {4,10,2,8} = nx + 1 Using Progression 1.0;Transfinite Line {3,9,1,11} = ny + 1 Using Progression 1.0;Transfinite Line {14,18,13,22} = nz + 1 Using Progression 1.0;Transfinite Surface {6} = {3,2,1,4};Transfinite Surface {27} = {5,14,2,3};Transfinite Surface {15} = {5,3,4,6};Transfinite Surface {28} = {6,10,14,5};Transfinite Surface {23} = {14,2,1,10};Transfinite Surface {19} = {6,10,1,4};Recombine Surface {27,23,6,19,15,28};// Top surfacePhysical Surface(33) = {23};// Bottom surfacePhysical Surface(34) = {15};// Left surfacePhysical Surface(35) = {27};// Right surfacePhysical Surface(36) = {19};// Front surfacePhysical Surface(37) = {28};// Back surfacePhysical Surface(38) = {6};// Box volumePhysical Volume (39) = {out[1]};