When an Magnetomechanics, Shell multiphysics interface is added using the Model Wizard, a Deforming Domain and a Symmetry/Roller nodes are added automatically in Model Builder under the Definitions node. These nodes serve to represent domains and boundaries where the mesh can deform. By default, both nodes have empty selection. Under the Deforming Domain, you can select those domain that represent nonsolid dielectric materials such as air, fluid, and free space. However, this is only needed if the boundaries of such domains experience significant changes due to the deformation or rotation of the adjacent solid domains. Otherwise, the moving mesh computations could just introduce unnecessary overhead and nonlinearity in the model (see Deformed Mesh Fundamentals).

Under the Deforming Domain, you can also choose the Mesh smoothing type, by default set to Yeoh. More information of the smoothing type can be found in the Deforming Domain chapter in the COMSOL Multiphysics Reference Manual.

By default, the mesh is fixed at all exterior boundaries of the geometry. Use the Symmetry node to select the exterior boundaries, where the mesh can slide along the boundary. You can also add other types of boundary conditions for the mesh motion, for details see Moving Mesh Features in the COMSOL Multiphysics Reference Manual.