S2N is the simpler method. The algorithm determines the nodal area allocated to each master surface node and then connects each master node to one of the slave nodes on a nearest-neighbor basis. The contact area always equals the entire master surface area. If only one slave node is present, then all master nodes are connected to this common slave node on an area weighted basis. Convection and radiation handling is the same in this regard, differing only in how the heat transfer coefficient is defined, and in whether couplings will be linear or radiation SINDAG conductor types.

The slave nodes may be any nodes in the model. Slave nodes may have temperature or heat loads specified on them, or may be connected to another part of the model. Perhaps most importantly, these nodes can be linked for advection heat transfer, coupling the surface to fluid flow, and not just static ambient nodes.