Methods, systems, and apparatuses are described for determining deformation of gingiva. A three-dimensional (3D) digital model of an archform comprising a representation of gingiva and at least one tooth may be received. The 3D model may comprise a 3D mesh describing a surface of the gingiva and the at least one tooth. The 3D mesh may be separated into a gingiva mesh and a tooth mesh. A set of shared vertices in the gingiva mesh and the tooth mesh may be identified. A tooth-movement displacement may be applied to the vertices in the tooth mesh and the vertices in the set of shared vertices. A vertex-specific displacement may be determined for the remaining vertices in the gingiva mesh by solving a harmonic equation. The 3D model may be updated.
