Reckoning

Reckoning / Shape / Prismoid

Solid · Prisms and pyramids

Prismoid

Two parallel rectangular ends of different sizes joined by flat faces, as in a cutting, embankment or hopper.

Drag to turn · pinch or scroll to zoom

Dimensions

Results

volume V

Formulas

The prismoidal formula is exact whenever the cross-section area changes as a quadratic in height, which is true for any prismoid. M is the mid-height section, not the average of the ends.

Checked: the V formula agrees with a Monte Carlo measurement of the shape itself, made from its geometric definition, every time the site is built.

Topology lens

Topologically a ball. Its surface has V = 8 vertices, E = 12 edges and F = 6 faces, and V − E + F = 2, as for every convex polyhedron (Euler, 1758). More on the lens.