Cantellation (geometry)

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A cantellated cube - Red faces are reduced. Edges are bevelled, forming new yellow square faces. Vertices are truncated, forming new blue triangle faces. Small rhombicuboctahedron.png
A cantellated cube - Red faces are reduced. Edges are bevelled, forming new yellow square faces. Vertices are truncated, forming new blue triangle faces.
A cantellated cubic honeycomb - Purple cubes are cantellated. Edges are bevelled, forming new blue cubic cells. Vertices are truncated, forming new red rectified cube cells. Cantellated cubic honeycomb.jpg
A cantellated cubic honeycomb - Purple cubes are cantellated. Edges are bevelled, forming new blue cubic cells. Vertices are truncated, forming new red rectified cube cells.

In geometry, a cantellation is a 2nd-order truncation in any dimension that bevels a regular polytope at its edges and at its vertices, creating a new facet in place of each edge and of each vertex. Cantellation also applies to regular tilings and honeycombs. Cantellating a polyhedron is also rectifying its rectification.

Contents

Cantellation (for polyhedra and tilings) is also called expansion by Alicia Boole Stott: it corresponds to moving the faces of the regular form away from the center, and filling in a new face in the gap for each opened edge and for each opened vertex.

Notation

A cantellated polytope is represented by an extended Schläfli symbol t0,2{p,q,...} or r or rr{p,q,...}.

For polyhedra, a cantellation offers a direct sequence from a regular polyhedron to its dual.

Example: cantellation sequence between cube and octahedron:

Cube cantellation sequence.svg

Example: a cuboctahedron is a cantellated tetrahedron.

For higher-dimensional polytopes, a cantellation offers a direct sequence from a regular polytope to its birectified form.

Examples: cantellating polyhedra, tilings

Regular polyhedra, regular tilings
FormPolyhedraTilings
CoxeterrTTrCOrIDrQQrHΔ
Conway
notation
eTeC = eOeI = eDeQeH = eΔ
Polyhedra to
be expanded
Tetrahedron Cube or
octahedron
Icosahedron or
dodecahedron
Square tiling Hexagonal tiling
Triangular tiling
Uniform polyhedron-33-t0.png Uniform polyhedron-33-t2.png Uniform polyhedron-43-t0.svg Uniform polyhedron-43-t2.svg Uniform polyhedron-53-t0.svg Uniform polyhedron-53-t2.svg Uniform tiling 44-t0.svg Uniform tiling 44-t2.svg Uniform tiling 63-t0.svg Uniform tiling 63-t2.svg
Image Uniform polyhedron-33-t02.png Uniform polyhedron-43-t02.png Uniform polyhedron-53-t02.png Uniform tiling 44-t02.svg Uniform tiling 63-t02.svg
Animation P1-A3-P1.gif P2-A5-P3.gif P4-A11-P5.gif
Uniform polyhedra or their duals
Coxeterrrt{2,3}rrs{2,6}rrCOrrID
Conway
notation
eP3eA4eaO = eaCeaI = eaD
Polyhedra to
be expanded
Triangular prism or
triangular bipyramid
Square antiprism or
tetragonal trapezohedron
Cuboctahedron or
rhombic dodecahedron
Icosidodecahedron or
rhombic triacontahedron
Triangular prism.png Triangular bipyramid2.png Square antiprism.png Square trapezohedron.png Uniform polyhedron-43-t1.svg Dual cuboctahedron.png Uniform polyhedron-53-t1.svg Dual icosidodecahedron.png
Image Expanded triangular prism.png Expanded square antiprism.png Expanded dual cuboctahedron.png Expanded dual icosidodecahedron.png
Animation R1-R3.gif R2-R4.gif

See also

Related Research Articles

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