Euhedra and Euhedra-Lite (for teaching point group symmetry, and more)
Euhedra is a crystal shape drawing program written by Bill Tislar, of T&T Technology. Bill has created a lite version, Euhedra-L, that can open and manipulate crystal models that have already been created but will not allow access to the information used to create those models (e.g. symmetry, Miller indices of forms, etc.). Thus, students can use this to view and manipulate crystal models, similar to having wooden models in hand (Early Crystal Models), but do not have access to the information that they may be asked to find by inspecting these models. The standard version has full functionality and an extensive help menu. Windows and Mac versions of both the standard and lite versions are available in the zip files below. Both versions of the program and the models are free of charge.
Students at Miami University (Christian Anderkin, Stephanie Mounce and Madeline Murchland) and John Rakovan have created a library of crystal shape models for use in Euhedra Lite. These include crystals with individual forms and form combinations from all crystal systems. They are available in the Miami Models.zip file below. In addition, a smaller set of models that utilizes the more advanced graphics capabilities of Euhedra is available (samples.zip)
One exercise that is used for teaching symmetry with wooden crystal models requires students to find all of the symmetry present in a model by inspection. They are then given a table with all of the point groups, their Hermann-Mauguin symbols, and the symmetry content of each. By comparing their results to the table, students can then determine the point group of that crystal model. I take three weeks of lab for this, and some additional exercises (e.g. stereograms of the crystals), starting with triclinic and monoclinic crystals, then orthorhombic and triclinic, and finally hexagonal and isometric. Of course, many other exercises are possible, and we hope that this resource will make creation of those exercises more tractable for teachers.
For the exercise described above it is recommended that teachers NOT share this link with students, but download all of the materials and then indipendently supply students with the zip files for the lite versions of the program, the crystal models, samples, and the point group pdf, as well as the link to the student tutorial on use of Euhedra-lite. This avaoids easy access to the exercise answers.
Materials for download:
Euhedra Lite for Windows (Euhedra2-0-1-L_Win.zip)
Euhedra Lite for Mac* (Euhedra2-0-1-L_Mac.zip)
Euhedra Standard for Windows (Euhedra2-0-1-Standard_Win.zip)
Euhedra Standard for Mac* (Euhedra2-0-1-Standard_Mac.zip)
Miami Crystal Models (Miami Models.zip)
Point Groups (Point Groups.pdf)
A video tutorial for Euhedra-Lite (for students) is available
A video tutorial for Euhedra-Lite (for teachers) is available at: https://youtu.be/CAJlDK8wivk
A video tutorial for Euhedra (for teachers and advanced users) is available at: https://youtu.be/wrstXobjsbw
Note: The program Euhedra has been modified since creation of the tutorial and a few things may be different. Additions described in the Euhedra-Lite tutorial are now part of Euhedra (including "Set Orientation" and "Reference Marker" ). Also, you may need to initiate the program using the Euhedra.bat file rather than the Euhedra.jar file, described in the tutorial.
John Rakovan and Bill Tislar
* A little more information:
Euhedra is a powerful, flexible and easy-to-use creation tool. It is written entirely in the Java programming language for use on Apple Macintosh and Microsoft Windows desktop and laptop computers. Euhedra requires at least Java Runtime Environment (JRE) version 1.5. The JRE provides the libraries, the Java Virtual Machine, and other components needed to run Java applications. If your computer does not have the JRE installed, or you need to upgrade the existing version, you can download it from the Internet. Because of issues between Mac and Java there may be problems when trying to run Euhedra and Euhedra Lite. View the Readme file in the zip distrubution file for Mac versions for help.
Euhedra's unique feature, which sets it apart from similar modeling tools, is its outstanding 3D graphics that make crystal models look real. Euhedra's graphics not only let you create models of opaque minerals with natural colors and lusters, but also models of transparent minerals that exhibit true refractive transparency. Euhedra provides tools that enable you to construct 3D models of any euhedral crystal or contact twin, then view and interact with the model in a simple virtual reality environment. You can adjust the attributes of the model and its viewing environment so that the model looks like a real crystal.