The Deformed Geometry (dg) interface (), found under the Mathematics>Deformed Mesh branch () when adding a physics interface, can be used to study how physics changes when the geometry, here represented by the mesh, changes due to an externally imposed geometry change. The difference between the Deformed Geometry and Moving Mesh interfaces is that the former defines a deformation of the material frame relative to the geometry frame, while the latter defines a displacement of the spatial frame relative to the material frame. The Deformed Geometry interface can be used in cases where the original geometry model shrinks or grows by removal or addition of material. For example, it can be used for shape optimization (geometry shrinks and grows at different places simultaneously), corrosion (geometry shrinks), or electrodeposition (geometry grows).

The Label is the default physics interface name.

The Name is used primarily as a scope prefix for variables defined by the physics interface. Refer to such physics interface variables in expressions using the pattern <name>.<variable_name>. In order to distinguish between variables belonging to different physics interfaces, the name string must be unique. Only letters, numbers, and underscores (_) are permitted in the Name field. The first character must be a letter.

The default Name (for the first physics interface in the model) is dg.

Specify the spatial coordinates of the base frame for the Deformed Geometry interface — the geometry frame — in the Geometry frame coordinates fields. The default is uppercase versions of the spatial coordinates followed by a lowercase g (for example, Yg). You can change the names in the fields for the First, Second, and Third coordinate. The field labels include the default spatial coordinate names in parentheses.

The Geometry shape order setting controls the order of polynomials used for representing the geometry shape in the material frame. The same order is used for Lagrange shape functions defining the mesh position in domains where Free displacement has been activated.