Incorporating 3-dimensional models in online articles.
BACKGROUND
The aims of this article are to introduce the capability to view and interact with 3-dimensional (3D) surface models in online publications, and to describe how to prepare surface models for such online 3D visualizations.


METHODS
Three-dimensional image analysis methods include image acquisition, construction of surface models, registration in a common coordinate system, visualization of overlays, and quantification of changes. Cone-beam computed tomography scans were acquired as volumetric images that can be visualized as 3D projected images or used to construct polygonal meshes or surfaces of specific anatomic structures of interest. The anatomic structures of interest in the scans can be labeled with color (3D volumetric label maps), and then the scans are registered in a common coordinate system using a target region as the reference. The registered 3D volumetric label maps can be saved in .obj, .ply, .stl, or .vtk file formats and used for overlays, quantification of differences in each of the 3 planes of space, or color-coded graphic displays of 3D surface distances.


RESULTS
All registered 3D surface models in this study were saved in .vtk file format and loaded in the Elsevier 3D viewer. In this study, we describe possible ways to visualize the surface models constructed from cone-beam computed tomography images using 2D and 3D figures. The 3D surface models are available in the article's online version for viewing and downloading using the reader's software of choice. These 3D graphic displays are represented in the print version as 2D snapshots. Overlays and color-coded distance maps can be displayed using the reader's software of choice, allowing graphic assessment of the location and direction of changes or morphologic differences relative to the structure of reference. The interpretation of 3D overlays and quantitative color-coded maps requires basic knowledge of 3D image analysis.


CONCLUSIONS
When submitting manuscripts, authors can now upload 3D models that will allow readers to interact with or download them. Such interaction with 3D models in online articles now will give readers and authors better understanding and visualization of the results.
Assistant professor, Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan, Ann Arbor, Mich. Electronic address: luciacev@umich.edu.
Lucia H S
LH
Cevidanes
Associate professor, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; CNPq Researcher and postdoctoral fellow, School of Dentistry, University of Michigan, Ann Arbor, Mich.
Antonio C O
AC
Ruellas
President, Kitware SAS, Lyon, France.
Julien
J
Jomier
Assistant professor, Department of Orthodontics, School of Dentistry, University of North Carolina, Chapel Hill, NC.
Tung
T
Nguyen
Software engineer, Isomics Inc, Cambridge, Mass.
Steve
S
Pieper
Software engineer, Neuro Image Research and Analysis Laboratory, Department of Psychiatry, University of North Carolina, Chapel Hill, NC.
Francois
F
Budin
Associate professor, Neuro Image Research and Analysis Laboratory, Department of Psychiatry, University of North Carolina, Chapel Hill, NC.
Martin
M
Styner
Assistant professor, Neuro Image Research and Analysis Laboratory, Department of Psychiatry, University of North Carolina, Chapel Hill, NC.
Beatriz
B
Paniagua
D003196:Computer Graphics; D054893:Cone-Beam Computed Tomography / Q000379:methods; D005147:Facial Bones / Q000033:anatomy & histology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D016247:Information Storage and Retrieval; D020407:Internet; D008334:Mandible / Q000033:anatomy & histology; D008437:Maxilla / Q000033:anatomy & histology; D008953:Models, Anatomic; D009862:Online Systems; D010506:Periodicals as Topic; D011643:Publishing; D012886:Skull / Q000033:anatomy & histology; D012984:Software