Methods, systems, and apparatus, including medium-encoded computer program products, for a machine learning approach for piecewise linear interface construction include: obtaining a cell fraction for a mesh cell in a mesh, a normal vector perpendicular to a linear interface for the mesh cell, and geometry information of the mesh cell, wherein the geometry information includes at least two data values; normalizing the geometry information of the mesh cell to reduce the at least two data values to at least one data value; obtaining an output value from a machine learning algorithm, previously trained using normalized geometry information of multiple different cells of a same mesh type as the mesh cell; determining the linear interface for the mesh cell based on the output value, the normal vector and the geometry information; using the linear interface for the mesh cell in numerical simulation processing of the mesh.