delim $$
NAME
poly - polyhedron database
DESCRIPTION
The directory /usr/lib/polyhedra contains an index file and
many polyhedron description files, each describing a solid
polyhedron and its (not necessarily unique) planar net.
Each line of the index file consists of a polyhedron's num-
ber followed by a horizontal tab and the polyhedron's name.
The polyhedron's number is also the name of its description
file. The routines of poly(3) read such description files.
Each description file consists of a number of fields. Each
field begins with a line consisting of `:' and the field
name. The field continues until the next header line or end
of file. Some fields contain values, which consist of a
floating point number optionally followed by an algebraic
expression enclosed in `[]', or angles, which are a value in
radians and optionally two more values (sin and cos) sepa-
rated by `@'. The fields include, but are not limited to,
number The polyhedron's number.
name The polyhedron's name, less than 128 characters
long and not capitalized.
symbol The Schlaefli symbol, a tab, and the Johnson sym-
bol for the polyhedron, given in eqn(1) style with
delimiters `@@'.
dual The name of the dual polyhedron optionally fol-
lowed by a horizontal tab and the number of the
dual.
vertices The first line is the number of vertices, which
follow, one per line. Each vertex has a coordi-
nate (three values separated by spaces), a number
n, and n face,edge pairs that surround the vertex.
faces The first line contains the number of faces and
the maximum number of vertices in any face. The
remaining lines are the faces, each with a vertex
count n, followed by 2n vertex numbers (planar,
solid), 2n edge numbers (planar, solid), and n
angles. The vertices of each face are listed in
the same order for both the planar and solid
forms: counter-clockwise as viewed from above the
planar net (i.e. from z>0) which generally corre-
sponds to outside the solid polyhedron.
edges The first line contains the number of edges. Each
edge is one line: face1 vertex1 face2 vertex2
length angle. The length is a value.
summary The three lines summarise the different kinds of
faces, vertices and edges respectively. Each line
POLY(5) (bowell) POLY(5)
consists of a total and a list of count example
symbolic triples; where example is an index into
the appropriate list and symbolic is given in
eqn(1) style with delimiters `@@'.
EOF The end of the polyhedron's description. (Another
polyhedron description may follow in this file.)
An expression in a value gives the exact value in the syntax
of bc(1) using these functions: a(x) = arctan(x), b(x) =
cubrt(x), c(x) = cos(x), d(x) = tan(x), p = pi, q(x) = x^2,
r(x) = arccos(x), s(x) = sin(x), t = phi = (1 + sqrt(5))/2.
The code may include assignments but does not include white
space.
FILES
index file
description files
SEE ALSO
poly(3), poly(7)