Polyhedra

This is a set of programs to generate, modify, and view various polyhedra. These all use the OFF format as an interchange format which is used by other geometry programs.

View basic polyhedra

Try:

java -jar polyhedra.jar cube -c red | java -jar polyhedra.jar view -

Alternatively:

java -jar polyhedra.jar view -- cube -c red

Operate on polyhedra

Try:

java -jar polyhedra.jar cube -c red | java -jar polyhedra.jar ambo -c yellow | java -jar polyhedra.jar view -

This can also be specified using the construct generator. Note the order of operations is reversed from the above.

java -jar polyhedra.jar construct 'ambo -c yellow' 'cube -c red' | java -jar polyhedra.jar view -

Alternatively:

java -jar polyhedra.jar view -- construct 'ambo -c yellow' 'cube -c red'

Using Conway polyhedron notation

Try:

java -jar polyhedra.jar construct aC | java -jar polyhedra.jar view -

Alternatively:

java -jar polyhedra.jar view -- construct aC

You can pass arguments in curly braces:

java -jar polyhedra.jar construct 'a{-c yellow}C{-c red}' | java -jar polyhedra.jar view -

Alternatively:

java -jar polyhedra.jar view -- construct 'a{-c yellow}C{-c red}'

Reading and writing OFF files

In addition to piping polyhedra from one command to another, you can use OFF files as an intermediary.

java -jar polyhedra.jar cube -c red | java -jar polyhedra.jar ambo -c yellow > cuboctahedron.off
java -jar polyhedra.jar view cuboctahedron.off

Alternatively:

java -jar polyhedra.jar construct 'ambo -c yellow' 'cube -c red' > cuboctahedron.off
java -jar polyhedra.jar view cuboctahedron.off

Alternatively:

java -jar polyhedra.jar construct 'a{-c yellow}C{-c red}' > cuboctahedron.off
java -jar polyhedra.jar view cuboctahedron.off

Alternatively:

java -jar polyhedra.jar cube -c red > cube.off
java -jar polyhedra.jar ambo -c yellow < cube.off > cuboctahedron.off
java -jar polyhedra.jar view cuboctahedron.off

Topology vs geometry

Note that most operations will result in a unique topology but not a unique geometry. Many operations have several options to specify how the geometry is created. Compare the following:

java -jar polyhedra.jar view -- construct 'kis -h 1.3' icosahedron

java -jar polyhedra.jar view -- construct 'kis -h 0.3' icosahedron

java -jar polyhedra.jar view -- construct 'kis -s' icosahedron

java -jar polyhedra.jar view -- construct 'kis -e' icosahedron

Furthermore, the result of any operation is not guaranteed to be convex, non-self-intersecting, or planar. Compare the nonplanar faces of:

java -jar polyhedra.jar view -- construct dual 'antiprism -n 6'

With the planar faces of:

java -jar polyhedra.jar view -- trapezohedron -n 6