Icosahedron - Quasi-Crystal
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EXAMP12

You must switch to the QSHAPE mode of operation with the Operate command in the Modes menu - see section IV-6 for principles and details of operation in this mode.

In the Symmetry dialog, you must supply the name of a Cartesian symmetry file - this is "Ih_example.sym", which is the file for icosahedral symmetry, as derived in the Cartesian (QSHAPE) Operating Mode section. You may need to Browse to the Samples folder to get the full pathname of this file. As the only form, enter {0 0 1} or {0.0, 0.0, 1.0} at a distance of one.

To get a pentagonal dodecahedron, enter {5.23607,0,1} as the only form. You can also try {010}, a rhombic triacontahedron.

As given above this example uses the orientation for the icosahedral groups from the trial-and-error example for SYMGR (see Help for SYMGRP). The symmetry file Ih_std.sym has the standard orientation for the groups, which is similar to that of cubic crystals, with the 3-fold axes (some of them) in the [111] position. Some simple forms for this orientation:

icosahedron: {1,1,1}
pentagonal dodecahedron: {0.525727, 0.850653, 0}
rhombic triacontahedron: {100}