POLY(5) POLY(5)
NAME
poly - polyhedron database
DESCRIPTION
The directory /usr/lib/polyhedra contains an index file and
many polyhedron description files. The index file consists
of lines composed of the polyhedron number 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 _p_o_l_y(3) read such description files.
The description file consists of a number of fields. A
field header is a line with an initial `:'. The remainder
of the line is the field name. Fields start with a field
header line and are terminated by the next field header line
or by end of file. A polyhedron's description is terminated
by the field `EOF'. The fields include, but are not limited
to,
number the polyhedron's number (written and read with
the %d printf/scanf format).
name the polyhedron's name is less than 128
characters long and is not capitalized.
symbol the _e_q_n(1) input for two symbols separated by a
tab; the Johnson symbol, and the Schlafli
symbol.
dual the name of the dual polyhedron optionally
followed by a horizontal tab and the number of
the dual.
vertices the first line contains the number of vertices.
The vertices are arranged one per line as an
(_x,_y,_z) coordinate of white-space separated
values (described below). The vertices are
implicitly numbered starting at zero.
net the first line contains the number of faces and
the maximum number of vertices in a face. The
remaining lines are the faces in the planar net.
Each face has a vertex count followed by the
vertex numbers. The vertices are listed in
counter-clockwise order as viewed from outside
the polyhedron.
hinges the first line contains the number of hinges in
the planar net. The remaining lines are hinge
connections. The format is _f_a_c_e_1 _s_i_d_e_1 _f_a_c_e_2
_s_i_d_e_2 _v_a_l_u_e. Sides are numbered from zero. If
the dihedral (_v_a_l_u_e) is greater than J, it is a
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POLY(5) POLY(5)
reflex or re-entrant hinge.
solid the first line contains the number of faces and
the maximum number of vertices in a face. The
remaining lines are the faces in the 3D
polyhedron. Each face has a vertex count
followed by the vertex numbers. The vertices
are listed in counter-clockwise order as viewed
from outside the polyhedron.
dihedral the first line contains the number of distinct
dihedrals. Each dihedral starts on a new line
and has a count and a value. If the count is
non-zero, then that many _f_a_c_e _e_d_g_e pairs (one
per line) follow the dihedral value.
EOF the end of the polyhedron's description.
A value consists of a floating point number optionally
followed by a expression enclosed by `[]'. The expression
is the exact value represented in _b_c(1) code with the
following function meanings: a(x) = tan-1(x), b(x) = (x)1/3,
c(x) = cos(x), d(x) = tan(x), p = J, q(x) = x2,
r(x) = cos-1(x), s(x) = sin(x), t = U. The code may include
assignments but does not include white space.
FILES
/usr/lib/polyhedra/index index file
/usr/lib/polyhedra/[0-9]* description files
SEE ALSO
poly(3), poly(7)
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