Use a Scaling System () to create a system that maps the geometry, as represented by the independent coordinates of an underlying frame, onto a virtual geometry represented by virtual scaling system coordinates. Physics interfaces that support infinite elements or perfectly matched layers accept the scaling system coordinates as being the physical domain, in which the underlying frame coordinates are seen as a parameterization. Therefore, using a scaling coordinate system you can arbitrarily deform the domain, essentially in the same way as when using Deformed Geometry with a Prescribed Deformation node.

The selected frame coordinates (the setting is invisible if there is only one frame) are seen as a parameterization of the “true geometry” in which the physics is solved. What you specify in the Coordinate mapping table is therefore a “true position” for each point in the mesh, expressed in the frame coordinates. When applied to a domain with a compatible material model in a physics interface, the equations in that domain are first reformulated in terms of the virtual x1, x2, and x3 coordinates but then automatically mapped back to the frame coordinates. This leads to explicit transformation expressions appearing in the equations.

Under Coordinate mapping, the Coordinate column displays the virtual coordinate names with the Expression column displaying the map from underlying frame coordinates to virtual coordinates. The default expressions are the spatial coordinates x, y, and z, which means no scaling.