Use FixedMesh to keep the mesh fixed on edges (3D) or boundaries (2D) while remeshing the faces (3D) or domains (2D).
Use model.component(<ctag>).mesh(<tag>).feature(<ftag>).create(<ftag1>,"FixedMesh") to keep meshes on a selection of edges (3D) or boundaries (2D) fixed for the feature
<ftag1> that can be any of the types
RemeshFaces or
RemeshDomains, respectively.
Use model.component(<ctag>).mesh(<tag>).feature(<ftag>).feature(<ftag1>).selection() to specify the edge (3D) or boundary (2D) selection.