rundhet

Rundhet is a term used in Danish and Norwegian to denote the quality or state of being round. In English, it is commonly translated as "roundness" or "curviness." The word derives from rund meaning round and the abstract noun suffix het.

In geometric terms, rundhet describes how closely a 2D shape or a 3D body approximates a perfect circle or sphere. There is no single universal metric; different disciplines employ related concepts such as circularity, roundness, and sphericity to quantify it. Circularity typically compares a shape’s area to the square of its perimeter, yielding a dimensionless index, while sphericity compares surface area to volume relative to a perfect sphere. In particle and grain analysis, roundness or form determines how smooth or angular a particle is.

Applications of rundhet span several fields. In geology and materials science, rundhet affects packing, flow, and strength; in manufacturing and product design, it influences aesthetics and fit; in biology, cellular or organ shapes may be described in terms of rundhet to indicate morphological traits.

Measurement of rundhet is typically performed with image analysis, microscopy, or 3D scanning, using algorithms that fit shapes or compute ratios. The choice of metric depends on context; a high rundhet generally indicates a smoother, more spherical or circular form, whereas a low rundhet indicates angularity or elongation.

See also: Roundness, Circularity, Sphericity, Ellipticity, Particle shape.