Flattening is the transfer of a spatially curved surface into a flat surface in order to obtain a planar cutting pattern for membrane structures. Since a curved surface is transferred into a flat horizontal projection area, the flattening process results in certain location, distance, angle, and size distortions, depending on the selected method.
In cartography, flattening is considered an important mapping condition for the transformation of the curved surface of the earth into a flat map. In structural engineering, flattening is used to determine flat cutting patterns for prestressed membrane structures.
Numerical planarization of arbitrary surfaces is possible for RFEM 5 using the [[#/en/products/older-products/rfem-add-on-modules/tensile-membrane-structures/rf-cutting-pattern RF‑CUTTING‑PATTERN] add-on module. In addition to pure flattening, this program also provides the option of taking compensations and allowances into account.