In FEMAP, users can freely generate their 3D meshes in whichever way they find convenient. The nodal and element connectivity information generated by FEMAP is directly used without any change by Fastflo. In Fastflo, a boundary tag number is assigned to each boundary segment. This boundary tag number needs to be defined in FEMAP before the mesh is converted to that of Fastflo, and this is achieved by using the Group ID number of FEMAP. In other words, users of FEMAP should regard the Group function of FEMAP as the way to define tag numbers of Fastflo. For example, in FEMAP, when a user sets up a Group with an ID number 4, all the nodes that belong to this Group will have a tag number 4 in Fastflo. In the next section, we show how a user can use FEMAP to generate a mesh for one particular geometry.