Poimutusjako

Poimutusjako is a term used to describe the distribution of folds, or poimutus, across a sheet or surface. In practice it refers to how crease lines are arranged—their density, orientation, spacing, and connectivity—and to how these properties influence the mechanical response of folded structures. The concept is used across disciplines such as origami engineering, packaging design, and material science to analyze and compare crease networks.

Etymology: The word is Finnish, combining poimutus (folding, pleating) and jako (distribution, sharing). In Finnish literature on folding and materials, poimutusjako denotes the statistical or geometric characterization of crease patterns and is sometimes translated as crease-distribution or crease-pattern statistics.

The theoretical framework treats crease networks as planar graphs where creases are edges meeting at vertices. Analyses may include crease density maps, orientation histograms, and local clustering measures. Models can assume random or deterministic patterns and often employ tools from geometry, graph theory, and statistical physics to describe scaling behavior and invariants such as average spacing or fractal dimensions.

Applications include guiding the design of foldable structures, predicting how a sheet will deform or deploy, and optimizing packaging materials to prevent unwanted creasing. In architecture and materials engineering, poimutusjako informs the development of deployable facades, flexible skins, and metamaterials with tunable stiffness.

Variations in definition and measurement reflect disciplinary differences, with ongoing research aimed at standardizing crease-pattern metrics and improving computational methods for analyzing large crease networks.