Some of the physics interfaces define a multiphysics analysis by themselves without being coupled to any other interface. This is the case when the physics interface is used for a coupling that is so strong that it does not easily lend itself to be separated into several physics interfaces. In other cases, a set of single physics interfaces, typically two, can be combined by the use of the Multiphysics node. For example, a Joule Heating analysis is defined as the combination of an Electric Currents interface and a Heat Transfer in Solids interface with an additional Electromagnetic Heat Source node under the Multiphysics node. The following lines of code illustrate the corresponding method calls, in a 2D case.

For a 3D case, change "geom1",2) to "geom1",3).

When using the Model Builder to set up a Joule Heating analysis, nodes in addition to those shown above will be created corresponding to Joule heating in thin shells, should they exist in the model, and temperature couplings if there are multiple field variables for electric potential and temperature.