Capsule (geometry)

A capsule (from Latin capsula, "small box or chest"), or stadium of revolution, is a basic three-dimensional geometric shape consisting of a cylinder with hemispherical ends.

[2][3][4][5] It can also be referred to as an oval although the sides (either vertical or horizontal) are straight parallel.

The shape is used for some objects like containers for pressurised gases, building domes, and pharmaceutical capsules.

In chemistry and physics, this shape is used as a basic model for non-spherical particles.

It appears, in particular as a model for the molecules in liquid crystals[6][3][4] or for the particles in granular matter.

[5] By this description, capsules can be straightforwardly generalized as Minkowski sums of a ball with a polyhedron.

[7][8] A capsule is the three-dimensional shape obtained by revolving the two-dimensional stadium around the line of symmetry that bisects the semicircles.