When the predefined Heat Transfer with Surface-to-Surface Radiation interface () is added (found under the Heat Transfer branch () of the Model Wizard or Add Physics windows), it combines the Heat Transfer in Solids and the Surface-to-Surface Radiation interfaces to model heat transfer by conduction, convection, and radiation in transparent media.

As a predefined multiphysics coupling, Heat Transfer in Solids and Surface-to-Surface Radiation interfaces are added to the Model Builder. In addition, a Multiphysics node is added, which automatically includes the Heat Transfer with Surface-to-Surface Radiation 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 Heat Transfer with Surface-to-Surface Radiation multiphysics coupling is also available when there is at least one of each of the following interfaces with the specified model activated: