Xenoposeidon: the crucial importance of 3D models

November 19, 2017

In writing the recent preprint “Xenoposeidon is the earliest known rebbachisaurid sauropod dinosaur” (Taylor 2017), it was invaluable to have a 3D model of the Xenoposeidon vertebra available. Here’s a short clip of viewing the model in the free MeshLab program. (It’s well worth full-screening to get the full impact.)

As I pan around, I look first at the upper margin of the posterior articular facet of the centrum, showing how the posterior margin of the neural arch shades into it — something that is not really apparent from photos, but needs the shifting perspectives that 3D offers to eliminate the interpretation that this contiguous border is due to damage.

Then I zoom in on the complex of laminae at the top of the left side of the neural arch, and explore the shapes of the intersections (ACPL with lateral CPRL, and PCDL with CPOL).

Finally I look at the distinctive sets of laminae on the anterior face of the vertebra which enclose the big, teardrop shaped centroparapophyseal fossa: lateral CPOL coming in from the lateral face of the arch, medial CPOL emerging from the pedicels, and the additional arched laminae that bound the space.

It’s just great to be able to do this. Time and again as I was preparing that manuscript, I went back to the model to check some detail — much as, twenty years earlier, Matt kept driving into the OMNH late at night to look at the Sauroposeidon holotype, to check out some idea he’d had as he worked on the description. The difference is, I didn’t need to drive into Norman, Oklahoma — or even London, England. The idea now of going back to trying to understand fossils from photos seems ridiculous.

A few years back, Matt wrote:

The idea of superseding photographs with 3D photogrammetric models is not original. I got religion last week while I was having beers with Martin Sander and he was showing me some of the models he’s made. He said that going forward, he was going to forbid his students to illustrate their specimens only with photographs; as far as he was concerned, now that 3D models could be cheaply and easily produced by just about everyone, they should be the new standard.

I’m totally on board with that, and said as much in the concluding paragraph of the new preprint.

The last thing I want to say here is to acknowledge the enormous amount of help I’ve had from Heinrich Mallison, digitizer extraordinaire at the Museum für Naturkunde Berlin. He’s invested many, many hours building models for me from my photos, pointing me to programs that I can use to view them, and helping me get started on making my own models. The greatest regret of my palaeontological life is that, when I happened to be in Berlin on 19th November 2008 and Heinrich invited me to come and watch the Germany-England friendly at his place, I couldn’t do it, and missed out on a pretty unique chance to see England beat Germany, in Germany, with a German. I doubt that chance will come up again any time soon.

I leave you with EmperorDinobot‘s life restoration of Xenoposeidon, which I stumbled across a few days ago. Obviously it’s wildly speculative, but I’m cool with that.

References

  • Taylor, Michael P. 2017. Xenoposeidon is the earliest known rebbachisaurid sauropod dinosaur. PeerJ PrePrints 5:e3415. doi: 10.7287/peerj.preprints.3415 [PDF] [PeerJ page]

 

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5 Responses to “Xenoposeidon: the crucial importance of 3D models”

  1. Kenneth Carpenter Says:

    Mike,
    I assume you know these models can be made into “3-D” pdfs that can manipulated & zoomed? Larry Wittmer has some at his website. It will be cool someday to have entire specimens bone-by-bone that others can study.
    Ken

  2. Mike Taylor Says:

    Yep. Among my To Dos for when I submit the revisions of this manuscript is to learn how to embed the model in a PDF, so I can supply it in that form as a second supplementary file. Also, a rotating video. We really do want to get to the point where we have whole databases of these things.

  3. Mike Taylor Says:

    I’ve looked into this a bit, but without much progress. According to Adobe’s own help page Add 3D models to a PDF page (Acrobat Pro) I should be able to insert a 3D file in U3D 3rd Edition or PRC format. But MeshLab does’t export PRC. It does claim to export U3D files, but (A) the process is very long and ends up emitting a very short TeX source file(!); and (B) Acrobat will not accept *.u3d files anyway.

    Anyone have any thoughts on this? Andy Farke, you’ve made 3D PDFs, right?

  4. Nick Gardner Says:

    Instead of embedding into PDFs which are less likely to be supported across platforms, why not use a web option like SketchFab?

    3D PDFs are soooo 2008!

    Two awesome examples

  5. Mike Taylor Says:

    Thanks, Nick, that’s new to me. Looks good to me. Problem is, unlike distributing a file, using this will be dependent on the site staying around. Still, since it will be an addition to the actual 3D mesh rather than a replacement, I think that’s OK.


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