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Basic Program Features
Software Archive
Bug Information
Disclaimer and Copyright

Basic Program Features

A variety of features make Wulffman both easy to use and powerful.

  • Simple graphical user interface
    All code functions are controlled from a main window, which spawns individual tool windows through which Wulffman is operated.

  • Extensive on-line help menus

  • Simple point group symmetry input
    • Predefined crystallographic groups
    • Predefined icosahedral groups
    • User-defined (non-)crystallographic groups

    Point groups can be selected through a simple interface where the user simply selects a crystal system and then a group within that system. User-defined groups can be built by specifying rotation or roto-inversion axes, mirror planes, and global inversion symmetry.

  • Intersection of multiple Wulff shapes
    Wulffman can keep track of multiple shapes each of which can have different symmetries and facet planes. It can then selectively intersect these shapes to model inclusions of one material in another.

  • Dynamic Wulff shape construction
    By specifying dynamic Wulff shape construction the user can modify the surafce energy of facets and watch the Wulff shape evolve under the specified changes. This allows for a clear demonstration of the effects of surface energy anisotropy on Wulff shapes.

  • Isotropic surface smoothing
    In many cases, only a few surface energies will be specified. With Wulffman, it is possible to require isotropic surface energy (set by the user) for all other facets. In this way, one can build partially-faceted structures with smooth connecting regions.

  • Measurement of Wulff shape properties
    Using the Measure module to Geomview, it is possible to measure all of the properties of a given Wulff shape: facet area, edge directions, vertex coordinates, and distance between points.

  • Slice Planes
    The user can input simple planes that cut the Wulff shape by specifying unique facets.

  • Information about crystallographic groups
    For the 32 crystallographic groups, stereographic projections of equivalent points and symmetry elements are available for inspection. These projections are equivalent to those found in standard references such as the International Tables of Crystallography .

  • Unit cell deformations / transformations
    It is possible to specify facet directions in either Cartesian or unit cell (hkl) coordinates. In the case where cell coordinates are used, the cell constants and angles can be modified where permitted; cell distortions become simple to implement in this way.

  • Precise control of Wulff shape properties
    Virtually all of the properties of the Wulff shape are under control of the user: visibile or invisible facets, facet colors, differentiation of facets and vertices, and axis display.

  • Three-dimensional printing
    Well, not really. Wulff shapes CAN be "flattened", however, with PostScript code generated so that they can be printed. Then with some cutting and pasting, a real three-dimensional Wulff shape can be made. Also known as ``A Wulff in sheets, folding''. Ha.

Center for Theoretical and Computational Materials Science, NIST
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Last updated: Sep 29, 2002