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download samples collected there by previous workers alongside           Inexpensive Virtual Reality (VR) and Augmented Reality (AR)                      GSA TODAY | www.geosociety.org/gsatoday
their papers. This could reduce a lot of wheel reinventing!”           software and hardware such as FreshAiR, Poppy3D, and Google
                                                                       Cardboard round off an effective, immersive, virtual field trip
  Not all rocks are suitable for modeling. The holes in scoriaceous    experience (Cherney, 2015; Crompton and De Paor, 2015). Future
basalt are particularly difficult to handle. Even with photogenic      possibilities include the use of 3D printers to create tactile models
specimens, it may be advisable to wait for overcast conditions in      for blind students (Doyle et al., 2016). They could include audio
order to avoid deep shadows that will not correspond to the sun’s      tracks that respond to the model’s orientation in a blind student’s
direction in later viewings. If very high resolution is required, and  hands via embedded fiducials.
rotation of the viewpoint is not essential, then GIGAmacro scans
may be preferable to a 3D model (Bentley, 2015). Some models             From the range of applications and future possibilities cited in
have gaps in the wireframe where they were in contact with a table     this paper, it seems likely that members of every division of GSA
or scanner turntable. These can be covered with a plain gray           could benefit from creating and sharing virtual specimens. They
surface in MeshLab, otherwise students may be confused by the          can even add an element of Dionysian entertainment to our
view into the interior of the specimen. As with art and sculpture      Apollonian geoscience studies (Kingsbury and Jones, 2009;
restoration, a plain gray patch is preferable to artistic interpreta-  Petchkovsky, 2012). In conclusion, it is hard to deny the fact that
tion of the missing material. If a model does not truly reflect a      “virtual rocks rock!”
verilith, that fact should be clearly stated. NextEngine distorts the
rock texture into tiger stripes at the turntable contact as seen in    ACKNOWLEDGMENTS
the Vredefort specimen. If not cleaned up, these artifacts need to
be pointed out to students.                                               This manuscript benefitted from comments by editor Jerry Dickens,
                                                                       reviewer John Geissman, and two anonymous reviewers. Melissa Beebe, Jessi
CONCLUSIONS                                                            Strand, Melissa Bates, Ernestine Brown, and Nathan Rogers assisted with
                                                                       scanning. This work was supported by the National Science Foundation
  Every (physical) surfer knows that the key to success is to not be   under grants DUE-1323419 and DUE-1540652.
too far ahead nor too far behind the currently breaking wave. It is
too soon to tell whether COLLADA models on Google Earth will           SUPPLEMENTARY MATERIALS
give way to glTF models on Cesium, or to the next unknown
wave. File formats such as .doc and .pdf persist for decades. Others     This paper is supported by a Supplemental Data Repository
such as .wpd fade away. Currently, the most sharable 3D model          item (see footnote 1) detailing techniques for creating virtual
formats include .dae and .obj, but this may quickly change.            specimens. There are also KMZ samples that can be downloaded
                                                                       and opened with the Google Earth desktop application, a sample
  Examination of rocks in the field remains important—indeed           HTML file with an embedded interactive COLLADA model, and a
vital—but field geologists face many restrictions. For the author,     sample 3D PDF contributed by Dr. Alan Pitts.
this has included encounters with armed security guards in Spain,
an angry muskox on Ellesmere Island, truculent farmers in              REFERENCES CITED
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tive GigaPan viewer to combined a GigaPan of the Massanutten                 and Bangash, H.A., 2014, Ground-based and UAV-based photogrammetry:
Sandstone with an instructor’s tracing of fossil tracks. Gessner et          A multi-scale, high-resolution mapping tool for structural geology
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the design principles in Lidal et al. (2012).                                (QTVR): A wondrous tool for presenting field trips, specimens, and
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                                                                             .hofstra.edu/J_B_Bennington/qtvr/qtvr_object.html (last accessed
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                                                                       Bentley, C., 2015, Four new GIGAmacro images of sedimentary rocks: AGU
                                                                             Blogosphere, http://blogs.agu.org/mountainbeltway/2015/12/23/four
                                                                             -new-gigamacro-images-of-sedimentary-rocks/ (last accessed 1 May 2016).

                                                                       Blenkinsop, T.G., 2012, Visualizing structural geology: From Excel to Google
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                                                                       Boggs, K.J.E, Dordevic, M.M., and Shipley, S.T., 2012, Google Earth models
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