10x10mm internal 8mm Openscad $fn=48; trubah_ext=10; trubah_int=8; connector_lenght=5; holediam=4; difference(){ union(){ translate([0,0,(trubah_ext-trubah_int)/4]){ cube([trubah_ext,trubah_ext,trubah_int+(trubah_ext-trubah_int)/2],center=true);} //x-axis /*translate([connector_lenght,0,0]){ cube