/polyhedra

Primary LanguageJava

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 -

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 -

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 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 icosahedron | java -jar polyhedra.jar kis -h 1.3 | java -jar polyhedra.jar view -

java -jar polyhedra.jar icosahedron | java -jar polyhedra.jar kis -h -0.3 | java -jar polyhedra.jar view -

java -jar polyhedra.jar icosahedron | java -jar polyhedra.jar kis -s | java -jar polyhedra.jar view -

java -jar polyhedra.jar icosahedron | java -jar polyhedra.jar kis -e | java -jar polyhedra.jar view -

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 antiprism -n 6 | java -jar polyhedra.jar dual | java -jar polyhedra.jar view -

With the planar faces of:

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