When this node is not used, the condition that applies is the continuity of the total flux. In the case of an interface between a porous medium domain and a moist air domain, this condition allows for evaporation and condensation to take place. This corresponds to the Allow evaporation/condensation behavior of the Free–Porous Interface subfeature. In the case of an interface between two porous medium domains, this condition can be different from the behavior of the Porous–Porous Interface subfeature, and also allows for evaporation and condensation to take place.