backres = DefineNumber[ 10, Name "Parameters/backres" ]; frontres = DefineNumber[ 50, Name "Parameters/frontres" ]; Point(1) = {2500, 500, 0, backres}; Point(2) = {0, 0, 0, frontres}; Line(1) = {2, 1}; Extrude {0, 10, 0} { Line{1};Layers{5};Recombine; } Extrude {0, 5, 0} { Line{2};Layers{10};Recombine; } Physical Surface(1) = {9}; Physical Surface(3) = {5}; Physical Line(1) = {2}; Physical Line(2) = {6}; Physical Line(3) = {7}; Physical Line(4) = {8}; Physical Line(5) = {1}; Physical Line(6) = {3}; Physical Line(7) = {4};