Each physics interface has a tag, which is of special importance when performing multiphysics simulations. This tag helps distinguish between physics interfaces and the variables defined by the physics interface have an underscore plus the physics interface tag appended to their names.

The Model Wizard is an easy way to select the physics interface and study type when creating a model for the first time, and physics interfaces can be added to an existing model at any time. Full instructions for selecting interfaces and setting up a model are in the COMSOL Multiphysics Reference Manual.

In 2D, in-plane and out-of-plane variants are available for problems with a planar symmetry as well as axisymmetric interfaces for problems with a cylindrical symmetry. See What Problems Can You Solve? for information about the available study types and variables. See also Overview of the User’s Guide for links to the chapters in this guide.