The Symmetry Axis Reference Point subnode is available in 2D axisymmetry, when there is an incident field defined in the parent node. Then this subnode is available as a default subnode to the Scattering Boundary Condition parent node.

The Symmetry Axis Reference Point subnode defines a reference position rref at the intersection point between the parent node’s boundary selection and the symmetry axis. If the parent selection doesn’t intersect the symmetry axis, the reference point is defined by the parent node’s selection or an added Reference Point subnode to the parent node.