DDN->Tetin allows to define boundaries conditions and to associate elements which constitute them (points, curves, surfaces).
At first, we create four families : entree, sortie, paroi and fluid. Then we associate corresponding elements. For the fluid family interior point is choosen to represent fluid domain.

Family list gives us informations about elements on each family.
To obtain an correct cell size (red cell in the following picture), we have to modify parameters in this section.


This step allows to create a .tin file which will be used in the mesh editor in the next step.