When the predefined Heat Transfer with Radiation in Participating Media interface () is added (found under the Heat Transfer branch () of the Model Wizard or Add Physics window), it combines the Heat Transfer in Solids and the Radiation in Participating Media interfaces to model heat transfer by conduction, convection, and radiation, including in participating (semitransparent) media.

As a predefined multiphysics coupling, Heat Transfer in Solids and Radiation in Participating Media interfaces are added to the Model Builder. In addition, a Multiphysics node is added, which automatically includes the Heat Transfer with Radiation in Participating Media multiphysics coupling feature.

The Heat Transfer in Solids interface provides features for modeling heat transfer by conduction, convection, and radiation in optically thick media. A Solid model is active by default on all domains. All functionality to include other heat transfer models, like Fluid, is also available.

The Radiation in participating media interface provides features to account for absorbed, emitted, and scattered radiation in a semitransparent medium. The radiative intensity equations defined in participating media domains are approximated with either the Discrete Ordinates Method or the P1 Approximation. It also computes the heating due to the propagation of rays. A Participating Medium model is active by default on all domains, and an Opaque Surface node is active on all boundaries. In addition, when Discrete ordinates method is selected, Continuity on Interior Boundary is also added.

The Heat Transfer with Radiation in Participating Media multiphysics coupling is also available when there is at least one of each of the following interfaces with the specified model activated: