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Virtual Rocks
GSA TODAY | AUGUST 2016 Declan G. De Paor, Department of Physics and Department of
Ocean, Earth, and Atmospheric Sciences, Old Dominion
University, Norfolk, Virginia 23529, USA, ddepaor@odu.edu
ABSTRACT
Three-dimensional digital models of geological objects are rela-
tively easy to create and geolocate on virtual globes such as Google
Earth and Cesium. Emerging technologies allow the design of
realistic virtual rocks with free or inexpensive software, relatively
inexpensive 3D scanners and printers, and smartphone cameras
linked to point-cloud computing services. There are opportunities
for enhanced online courses, remote supervision of fieldwork,
remote research collaboration, and citizen-science projects, and
there are implications for archiving, peer-review, and inclusive
access to specimens from inaccessible sites. Virtual rocks can be
gradually altered to illustrate geological processes such as weath-
ering, deformation, and metamorphic mineral growth. This paper
surveys applications in a wide range of geoscience subdisciplines
and includes downloadable examples. Detailed instructions are
provided in the GSA Supplemental Data Repository1.
INTRODUCTION
In recent decades, numerous virtual field trips have been
created to simulate in-person field excursions; however, one
aspect of physical fieldwork is not commonly replicated: virtual
explorers do not often return to their computer desktops with
collections of virtual rocks! There are multiple justifications for
creating interactive 3D digital models of rocks, minerals, fossils,
drill core, geo-archaeological objects, and outcrops. For example,
one can (i) reveal 3D features hidden inside solid specimens; (ii)
archive samples destined for destructive testing; (iii) prepare for
field trips and reinforce learning and retention after the fact; (iv) geologists Thiele et al. (2015) gained new insights into en échelon
aid peer-review and supplement electronic publications; (v) give
access to geological materials for disabled and other non-tradi-
tional students; and (vi) provide access to collections locked away
in storage drawers, given that museums and other repositories
display only a small fraction of their holdings.
The concept of a virtual specimen is not new. Following the
mechanical tomography of Sollas (1904), Tipper (1976) used a
grinding wheel to serial-section fossils. He traced outlines with a
digitizing tablet, created 3D models with a mainframe computer,
and interacted with them using a graphics storage tube (relatively
youthful readers can image-google “graphics storage tube”),
exploring previously hidden inner surfaces.
Virtual geological collections already exist online, and readers
may simply link content to their own virtual field trips, online
GSA Today, v. 26, no. 8, doi: 10.1130/GSATG257A.1.
1 GSA Supplemental Data Repository Item 2016173, detailing techniques for creating virtual specimens along with figure animations, is online at www.geosociety.org/
pubs/ft2016.htm. If you have questions, please contact GSA Today, P.O. Box 9140, Boulder, CO 80301-9140, USA; gsatoday@geosociety.org.
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courses, and social media pages. Reynolds et al. (2002) and
Bennington and Merguerian (2003) used QuickTime Virtual
Reality (QTVR) to display interactive digital specimens. The
Smithsonian Museum has a large collection of scanned 3D
objects (Smithsonian, 2016), and the British Geological Survey
(2016) has assembled more than 1,800 virtual fossils. Numerous
LiDAR models of outcrops have been made (Clegg et al., 2005;
McCaffrey et al., 2008; Buckley et al., 2010; see also Passchier,
2011, and VOG, 2016).
More recently, geoscientists have created many virtual speci-
mens for paleontological functional analysis, digital exchange of
research data, and teaching in a range of geoscience subdisci-
plines. For example, Pugliese and Petford (2001) revealed 3D melt
topology of veined micro-diorite, and Bates et al. (2009) estimated
dinosaur bone mass from models.
Modelers have long used 3D scanners, and, more recently, 3D
printers (Hasiuk, 2014) to create ever-more sophisticated virtual
objects. Cohen et al. (2010) reconstructed archaeological vessels
from virtual ceramic shards, harnessing the computer’s power to
solve 3D jigsaw puzzles. Engineering geologists Dentale et al.
(2012) used FLOW-3D® software to test a virtual breakwater built
out of individual virtual stones and accropodesTM. Medical
CT-scanning methodologies were used by Hoffmann et al. (2014)
to study buoyancy in virtual cephalopods, by Carlson et al. (2000)
for igneous texture studies, and by Pamukcu et al. (2013) to
examine glass inclusions in quartz crystals. Rohrback-Schiavone
and Bentley (2015) employed GIGAmacroTM hardware to create
grain-scale sedimentological models. Root et al. (2015) compared
models of Neolithic monuments in Ireland and the Middle East,
while Mounier and Lahr (2016) created a 3D model of the skull of
the common ancestor of humans and Neanderthals. Structural
vein formation, and Favalli et al. (2012) modeled outcrops, a
volcanic bomb, and a stalagmite. They concluded that the quality
of virtual outcrops or specimens is comparable to LiDAR outcrops
or laser-scanned specimens, respectively.
In recent years, the most exciting developments in 3D modeling
include the availability of smartphone apps and associated point-
cloud computing services that non-specialists can quickly master.
The purpose of this paper is to highlight the recent, current, and
potential future role of virtual specimens in diverse aspects of
geoscience education and research.
CREATING VIRTUAL SPECIMENS WITH SKETCHUP
Virtual specimens can be created with a digital camera and
SketchUp (2016). SketchUp exports a model as a COLLADA file
optionally zipped with a KML document and one or more texture