Chamfer (geometry)

Chamfered tetrahedron
(with equal edge length)
Conway notation	cT
Goldberg polyhedron	GPIII(2,0) = {3+,3}2,0
Faces	4 triangles 6 hexagons
Edges	24 (2 types)
Vertices	16 (2 types)
Vertex configuration	(12) 3.6.6 (4) 6.6.6
Symmetry group	Tetrahedral (Td)
Dual polyhedron	Alternate-triakis tetratetrahedron
Properties	convex, equilateral-faced
net

The chamfered tetrahedron (or alternate truncated cube) is a convex polyhedron constructed as an alternately truncated cube or chamfer operation on a tetrahedron, replacing its 6 edges with hexagons.

It is the Goldberg polyhedron G_III(2,0), containing triangular and hexagonal faces.

The truncated tetrahedron looks similar, but its hexagons correspond to 4 of the tetrahedrons vertices, rather than to its 6 edges.

Tetrahedral chamfers and related solids

chamfered tetrahedron (canonical)	dual of the tetratetrahedron	chamfered tetrahedron (canonical)
alternate-triakis tetratetrahedron	tetratetrahedron	alternate-triakis tetratetrahedron

Chamfered cube
(with equal edge length)
Conway notation	cC = t4daC
Goldberg polyhedron	GPIV(2,0) = {4+,3}2,0
Faces	6 squares 12 hexagons
Edges	48 (2 types)
Vertices	32 (2 types)
Vertex configuration	(24) 4.6.6 (8) 6.6.6
Symmetry	Oh, [4,3], (*432) Th, [4,3+], (3*2)
Dual polyhedron	Tetrakis cuboctahedron
Properties	convex, equilateral-faced
net

The chamfered cube is a convex polyhedron with 32 vertices, 48 edges, and 18 faces: 12 hexagons and 6 squares. It is constructed as a chamfer of a cube. The squares are reduced in size and new hexagonal faces are added in place of all the original edges. Its dual is the tetrakis cuboctahedron.

It is also inaccurately called a truncated rhombic dodecahedron, although that name rather suggests a rhombicuboctahedron. It can more accurately be called a tetratruncated rhombic dodecahedron because only the order-4 vertices are truncated.

The hexagonal faces are equilateral but not regular. They are formed by a truncated rhombus, have 2 internal angles of about 109.47° ${\displaystyle \cos ^{-1}(-{\frac {1}{3}})}$ and 4 internal angles of about 125.26°, while a regular hexagon would have all 120° angles.

Because all its faces have an even number of sides with 180° rotation symmetry, it is a zonohedron. It is also the Goldberg polyhedron GP_IV(2,0) or {4+,3}_2,0, containing square and hexagonal faces.

The chamfered cube is the Minkowski sum of a rhombic dodecahedron and a cube of side length 1 when eight vertices of the rhombic dodecahedron are at ${\displaystyle (\pm 1,\pm 1,\pm 1)}$ and its six vertices are at the permutations of ${\displaystyle (\pm {\sqrt {3}},0,0)}$.

A topological equivalent with pyritohedral symmetry and rectangular faces can be constructed by chamfering the axial edges of a pyritohedron. This occurs in pyrite crystals.

Pyritohedron and its axis truncation

Historical crystallographic models

The truncated octahedron looks similar, but its hexagons correspond to the 8 vertices of the cube, rather than to its 12 edges.

Octahedral chamfers and related solids

chamfered cube (canonical)	rhombic dodecahedron	chamfered octahedron (canonical)
tetrakis cuboctahedron	cuboctahedron	triakis cuboctahedron

Chamfered octahedron
(with equal edge length)
Conway notation	cO = t3daO
Faces	8 triangles 12 hexagons
Edges	48 (2 types)
Vertices	30 (2 types)
Vertex configuration	(24) 3.6.6 (6) 6.6.6
Symmetry	Oh, [4,3], (*432)
Dual polyhedron	Triakis cuboctahedron
Properties	convex

In geometry, the chamfered octahedron is a convex polyhedron constructed from the rhombic dodecahedron by truncating the 8 (order 3) vertices.

It can also be called a tritruncated rhombic dodecahedron, a truncation of the order-3 vertices of the rhombic dodecahedron.

The 8 vertices are truncated such that all edges are equal length. The original 12 rhombic faces become flattened hexagons, and the truncated vertices become triangles.

The hexagonal faces are equilateral but not regular.

Historical drawings of rhombic cuboctahedron and chamfered octahedron

Historical models of triakis cuboctahedron and chamfered octahedron

Chamfered dodecahedron
(with equal edge length)
Conway notation	cD] = t5daD = dk5aD
Goldberg polyhedron	GV(2,0) = {5+,3}2,0
Fullerene	C80[1]
Faces	12 pentagons 30 hexagons
Edges	120 (2 types)
Vertices	80 (2 types)
Vertex configuration	(60) 5.6.6 (20) 6.6.6
Symmetry group	Icosahedral (Ih)
Dual polyhedron	Pentakis icosidodecahedron
Properties	convex, equilateral-faced

The chamfered dodecahedron is a convex polyhedron with 80 vertices, 120 edges, and 42 faces: 30 hexagons and 12 pentagons. It is constructed as a chamfer of a regular dodecahedron. The pentagons are reduced in size and new hexagonal faces are added in place of all the original edges. Its dual is the pentakis icosidodecahedron.

It is also inaccurately called a truncated rhombic triacontahedron, although that name rather suggests a rhombicosidodecahedron. It can more accurately be called a pentatruncated rhombic triacontahedron because only the order-5 vertices are truncated.

The truncated icosahedron looks similar, but its hexagons correspond to the 20 vertices of the dodecahedron, rather than to its 30 edges.

Icosahedral chamfers and related solids

chamfered dodecahedron (canonical)	rhombic triacontahedron	chamfered icosahedron (canonical)
pentakis icosidodecahedron	icosidodecahedron	triakis icosidodecahedron

Chamfered icosahedron
(with equal edge length)
Conway notation	cI = t3daI
Faces	20 triangles 30 hexagons
Edges	120 (2 types)
Vertices	72 (2 types)
Vertex configuration	(24) 3.6.6 (12) 6.6.6
Symmetry	Ih, [5,3], (*532)
Dual polyhedron	triakis icosidodecahedron
Properties	convex

In geometry, the chamfered icosahedron is a convex polyhedron constructed from the rhombic triacontahedron by truncating the 20 order-3 vertices. The hexagonal faces can be made equilateral but not regular.

It can also be called a tritruncated rhombic triacontahedron, a truncation of the order-3 vertices of the rhombic triacontahedron.