The Symmetry, Interface node adds a symmetry boundary condition to the exterior boundaries of a layered shell. The following condition implements the symmetry condition on an axis or a flow divide:

The available options in the Apply to list are Top interface, Bottom interface, Exterior interfaces (which is the default setting), and Selected interfaces. With the last option you can select a set of interfaces and the layered material for which the boundary condition should be active. Note that the checkboxes for internal interfaces between layers are deactivated for the symmetry, interface node.

The top and bottom interfaces refer respectively to the upside and downside of the boundary, defined from the orientation of the normal vector. You can visualize the selected interfaces by clicking the Layer Cross Section Preview () and Layer 3D Preview () buttons.