22.4.16

Huesos impresos en 3D vs. huesos virtuales en el 1st IMERP-XIV EJIP


La tarde del 14 de Abril transcurría tranquilamente en Alpuente durante la celebración del XVI EJIP hasta que un joven se subió con lo que parecía un collar tribal africano a dar una charla. La charla versaba sobre una comparativa entre los resultados obtenidos manipulando esqueletos virtuales para estudiar el rango de movimiento frente a los obtenidos manipulando réplicas del esqueleto impreso a escala en 3D, y el collar africano era, ni más ni menos, que las vértebras cervicales impresas de Spinophorosaurus, que fue la cobaya para este estudio.

Este es el abstract (en inglés) del trabajo:

Digital range of motion analysis based upon high fidelity scanned fossils has proven to be a very useful tool to provide evidence on the motions that an extinct animal can or cannot perform. Such evidence, when accumulated for enough taxa, will allow studying the evolution of biomechanics on a macroevolutionary scale. This is of great interest particularly in sauropodomorph evolution, where an intense debate exists on their biomechanical capabilities (i.e. the life position of their necks). However, there are caveats to digital range of motion analysis inherent to the software and limits on its display capabilities (i.e. digital meshes have not "solid" properties, thus osteological stops have to be estimated visually). This may result in an under or overestima- tion of the range of motion.

In order to test this potential error, we ran a digital range of motion analysis with the digitized cervical vertebrae of Spinophorosaurus nigerensis, in Autodesk 3D Studio Max, and tested the results by manually manipulating 1:4 models of the same vertebrae obtained by 3D printing.

Although most results were similar in both analyses, it was determined that the osteological neutral pose (ONP, when zygapophyseal overlap is maximum and centra are as parallel as possible) was more dorsally deflected when manipulating the physical model, with parallel centra yet more separated, revealing potential large cartilage or synovial capsules. Lateral range of motion was found to be a little more restricted in the physical model as well, due an osteological stop not evident when digitally manipulating the files.

In conclusion, 3D printing allows testing range of motion hypothesis without damaging the origi- nal specimens, as well as an easier manipulation due the benefit of a smaller size and lower weight. The alignment of the centra was the most discre- pant result between both analyses.

-----
Imagen:
  • Daniel Vidal durante su charla en el XIV EJIP, capturado por el objetivo del insigne fotógrafo lusitano Pedro Mocho, al que desde este humilde rincón damos las gracias.