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.