Absurd Addendum to Gut Check

Yesterday, I posted some pictures that I took with a fisheye lens. As mentioned, one has to be hellishly careful not to get into the picture by accident. Well, I mentioned lying down on the floor…….

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Note the camera under Diplodocus‘ belly.

Also, I took an unintended selfie. My tripod head allows tilting the camera down to 90°, and up to 45°. If I want to tilt it any further, I need to reverse it: take it off, loosen the screw that fixes the holder plate to the camera, turn the plate around 180°, then fasten the screw again and set the camera back onto the tripod. I did this without turning the camera off, and because it was in liveview mode, where you can release the shutter by touching the liveview screen, and because I happened to brush against the screen when I set the camera back into the bracket….. well, the camera was, due to the rotation, pointing in the exact opposite direction of “upward at Giraffatitan;)

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There you go, critical looking palaeontologist with Elaphrosaurus. Needs a shave ;)

Posted in FUN!!!, photography | 2 Comments

Sauropod gut check

In the past I have posted a few times on unusual perspectives of our MfN dinosaurs, especially the big sauropods Giraffatitan (ex Brachiosaurus), Diplodocus and Dicraeosaurus. There’s one view that I didn’t write much about before, and I won’t write much today – but I’ll show you a few pictures. Gut check pics. Can you tell which is which?

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These photographs were all taken with a Canon EF 8-15 mm Fisheye lens set to 15 mm. Obviously a fisheye, but there’s way more this lens allows! Below, a few more “gut check” and other views of the dinosaur hall I took today.

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If you look closely, you can see the low railing that runs around the low platform under the dinosaurs. The lens allows depicting almost a hemisphere! My colleague Matteo Belvedere, who helped me with the pic taking, and I had to hide ourselves well so we wouldn’t be in the photos! In fact, I used the 10 second timer release on the shutter and laid myself flat on the ground next to the platform – which gave Matteo a good laugh ;)

By now, I suspect every last reader of this blog has found out what wonderful image these photographs remind us of. Julius Csontonyi’s wonderful fisheye view of a sauropod. One of the coolest bits I’ve seen in a loooong time. Here‘s one version on the web. Isn’t it great? My images were taken from under the animals, not just next to them, but the oddness of ther perspective is similar.

Now, to round this off, for two shots of the hall from a more conventional viewpoint.

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The latter shows off the huge size of Giraffatitan very well, as well as the hall’s overall classical proportions and architecture. And the great skylight. I makes for great lighting, but I must admit that it can be a challenge to photograph something big, as one invariably ends up photographing it against the light. In this case, shooting a series of different exposures and HDR-merging them helped ;)

 

 

 

 

 

Posted in Dicraeosaurus, Dinopics, Dinosauria, Diplodocus, Giraffatitan, MfN Berlin, photography, Sauropoda, Sauropodomorpha | 10 Comments

AMNH Feb 2015

A short while ago I paid a rather unexpected and sudden visit to the AMNH in New York. American Museum of Natural History – that name stands for one of the greatest museums in the world, and it has much more to offer than just absolutely cool dinosaur galleries. But hey, I’m a dino researcher, so guess where I was headed ;)

Aside from being the first ‘big’ natural history museum I remember visiting at age 10 (I do not count the back-then small and cramped SMNS in Stuttgart; mucho has changed there since, including an additional building much bigger than the old one), the AMNH has been a special place for my own research career. It has, therefore, popped up here and there on this blog a few times. Well, many times. Very many times.

This time, I happened to have a flight back to Germany on a Monday evening, but learned after booking it that I would run out of work in Pennsylvania on Thursday evening. So the question was: change the flight, or make use of the time in NY? As not staying for one Saturday night in the US makes the flights become some $220 more expensive, and as the rescheduling fee was another $210, the decision was simple: stay in NY and try to get into the AMNH collections! Luckily, I know collection manager Carl Mehling pretty well by now, and luckily Carl is a really great guy. I posted a fun photo of him a while ago, and he’s still a big, knowledgeable, kind and funny bear of a man. I emailed him about my predicament of being stuck in NY, and sent along the required official letter requesting access – and got back a rather short email: “Sounds good to me Heinrich. See you soon.” Typical Carl :)

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The AMNH’s  Central Park entrance with Teddy Roosevelt on his horse.

Thus I found myself at the entrance punctually at 9:30 in the morning, ready to fill my camera’s memory card….. One of the things I hoped to achieve during this short visit was going back to the wonderful oviraptor specimens from Mongolia stored at the AMNH. I had photogrammetrized them during my last visit (see here and here), but because I was young an stupid I forgot to use a big scale bar. ‘big’ being important because when you scale the 3D model, the error of where you place your marker on the photo is pretty much the same, absolutely, however big or small your scale bar is. So a longer scale bar means that the error in each marker’s position becomes proportionally less! Thus, the accuracy overall goes up. So this time, I brought bigger scale bars, and was hoping to be able to take a few additional photos of each specimen, with the big scale bars draped around them.

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Well, as those two samples show, I was able to access the specimens. Now I just had to find my old Photoscan project files, put the new photographs with the big scale bars into them, and re-scale. Here we go…… two scale bars of 50 cm each, and Photoscan calculates their errors as very slightly over 0.002 m (i.e., 2 mm!) each.

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I also took photographs of the Edmontonia mount and the Protoceratops mount I digitized last time, for the same purpose. However, as they are encased in glass, I had to lean the scale bars against the glass on one side of the mount, then go around to the other side and take photographs from there. Any distance from the glass means there will be too many reflections. No idea if this will work out; I’ll let you know!

Obviously, I checked out a bunch of other things, too. Some of this I can’t write about right now, but you’ll be let in on the secret in a few months – promise! What I can say is that I spent a lot of time photogrammetrizing some of the many well preserved foot bones of Albertosaurus the AMNH keeps in the collection.

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Bones like those in this drawer. I am always struck by a bit of institutional envy when I enter the AMNH main collections or the big bone room. Proper shelves and cabinets! A fairly flat and level floor! Our bone cellar has its own charm, with the wooden shelves and the brick floor, but for doing actual work in the room the AMNH is two leagues above us.

 

 

Posted in AMNH, Digitizing, Dinopics, Dinosauria, Khaan, Maniraptora, Oviraptorosauridae, photogrammetry, photography, Theropoda, Travels, Tyrannosauridae, Tyrannosaurus | 11 Comments

snaphots

“snapshot” – that word is usually used to describe an amateurish photograph (unless you are talking about a screen capture on your computer). But the term is not so much tied to the low level of professional knowledge as rather the haste/speed/lack of preparation that goes into taking the photograph. So the word has carried over into military use for a hastily taken shot – even for such a shot by an expert marksman. The same is true, obviously, for photography by experts: if there is no time, if you just yank up your camera and hit the trigger, it’s a snapshot, even if you’re Helmut Newton!

Now, obviously, an expert photographer will more often take snapshots that actually look like something, whereas us amateurs tend to produce, well….. erh…. let me just say that it’s a good thing that digital photography costs only the price of electrical power, and that I love the inventor of the “delete” button! And that better outcome quality is surely in part linked to the on average better equipment professional photographers and serious experienced amateurs lug around. It also correlates with knowledge of how to set up your camera so you’re ready for anything at short notice, and with practice.  And, to be perfectly honest, with not being lazy ;) Let me explain how and why on an example, one that’s putting this post within the range of the impending Theropod Thursday:

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A subadult ringbilled gull (Larus delawarensis) I photographed in New York, with the Peking and the Wavertree serving as the near-perfect frame. I caught the bird in flight and “froze” it perfectly – but only a half-second before I took the shot my camera had been dangling down by my leg. How did I do this? Am I a magician?

Certainly not – no magic involved at all! But two simple tricks and, admittedly, an OK camera. First of all, my camera is a fairly new DSLR, with a fairly new lens, which means it has a fast autofocus. And a smart one, too, that doesn’t get hung up on a tiny speck, but focusses quickly and reliably on whatever I ask it to focus on. If I handle the settings right, it’s point&shoot and the image will be in focus. A cell phone cam simply can’t do this, and even good compact cameras are usually hard pressed!

And secondly, I put it on settings that made the task easy. Here’s what you should do when you expect to be around birds, little children or other potential victims for snapshots:

–  set you camera to time variable mode (Tv for Canon). In this mode, you manually select the exposure time, and the camera tries to make aperture work for an OK exposure.
– select a short exposure time (here 1/1000 s). The shorter the less motion blur will you see, both from your moving the camera and from the subject you photograph moving versus the camera.
– check against the background you expect to photograph: can the camera come up with a well-exposed image with the settings you chose? If not, consider increasing the ISO value. I went to ISO 400 here, as I know this value gives OK images. For the shot above ISO 200 would have been possible (the image is F13!), but I was also expecting to shoot in the direction of the FDR Drive, which is a raised road, so that it’s kinda dark under it. And very low F-stops are not that great if your subject may be close to the camera. You may end up having part of it sharp, and parts already out of focus. If in doubt, let the camera take photos that are underexposed. You can always brighten them up on the computer. You can’t un-blur an image blurry from motion!
– depending on what you intend to photograph, decide between continuous, single-shot or some other autofocus mode.

So, now the camera is set up properly. I am a bit of a snob with regards to battery live, as I can always afford to carry enough spares. Therefore, I’ve set my camera not to switch off properly, but only “slumber” when there’s no action. This means that it comes back, ready to shoot, within a split-second if I press any button.

The second thing I do to make sure I am always ready for a snapshot is NOT dangling my camera from a long strap around my neck. I have a wrist strap, a short thing that serves as insurance only, and hand-carry my camera whenever I am in situations where I might be tempted to a snapshot. This means two things: I do not need to reach for my camera when an opportunity for a good photo comes around, and I do not have anything else in my right hand at that time!

So, when I see something, up comes the camera, and as I bring it up I lightly press the trigger. This turns the camera on, and by the time my eye is on the viewfinder it is ready to shoot. SNAP!

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Another ringbill. Rats of the Air, some call them. Whatever – they are pretty ;)

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Oh, a final hint: do not run out your zoom lens to the max length! With fast moving things close to you, a long lens means you spend a lot of time waving it around trying to find and focus on your subject. Rather, keep it short, and if there is time run out the zoom after acquiring your “prey”.

Oh, and if you want to read this advice again, but coming from someone who (as opposed to me) really knows what he’s talking about, go visit www.tornadoropa.eu/, the blog of my esteemed colleague Christian Neumann ;)

 

Posted in Aves, Dinopics, Dinosauria, How to, photography, Theropoda | 2 Comments

Theropod Thursday 51: a Spechtschmiede

It’s been a very long time since the last Theropod Thursday post, and I promise to increase the posting ratio a bit in the near future. Theropods are cool – after all, they are the sister group to the really cool dinosaurs, the Sauropoda that include my beloved Plateosaurus! But they are also extra cool because we can study things on them we simply can’t study on any other dinosaur group. That’s because theropods are the sole branch of the dinosaur tree that is still around. People call them birds, because the necessity to give a name to these feathery flying animals is older than the realization that they are just a part of the great overall dinosaurs, but at the core of even the most stupid chicken or tiny songbird there is a vicious predator hidden away that’s just waiting for someone to beat up!

Also, many birds are surprisingly smart – think corvids, the crows, magpies and ravens clan! But even much more mundane birds have some neat tricks up their feathery sleeves.  Here’s one bird that does something cool that I have known about forever, that I have seen traces of, and that I have actually watched being done – but never so far been able to get good photos of.

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Great Spotted Woodpecker (Dendrocopos major). They are quite common in Germany, and there are always several around our house. The first three years after we moved here to Berlin there was a breeding pair nesting very close by; I found young barely able to fly in our garden. Now there is a breeding pair close by, maybe in one of the trees at the edge of the forest 50 yards away. The bird in the picture, however, lives in Stuttgart, where I happened to get the rare chance to take photos down into a tree from a window at my parent’s flat. That’s nice for several reasons, one being that for once I was not pointing my camera at a bright background, which made balancing the exposure easier than a typical against-the-sky shot would have been. Another reason is this:

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The bird was busy hacking away at something on the branch, and not with the typical staccato beating that’s related to communication or wood&bark removal (to get at food living in and under the bark or in rotting wood). It also wasn’t the powerful rapid-fire hacking that’s used to dig cavities for nesting. Rather, what I saw was a series of deliberate individual picks, the sound of which (a bit like single shots of a nail gun two yards away) was what had drawn me to the open window in the first place. In between the pecks the bird looked at the object it was hacking at, and twice picked it up and put it back down:

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A walnut! A tiny one, as the tree was not properly grafted and thus grows only tiny nuts. Still, the ratio of dead nuts from this tree is low, and there’s lots of nuts, so it offers a reliable source of food in late summer for all those capable of opening the nuts.

What I was seeing in action here was the use of a Spechtschmiede, literally a woodpecker smithy or anvil. There seems not to be a special English term for this – we Germans have a penchant for creating those combined nouns for technical terms. Interestingly, there’s not only no special term for this, but also no mention of the associated behaviour in the English wikipedia or anywhere else. Basically, a Spechtschmiede is a place where woodpeckers (and others) are able to lodge an object tightly so that they can peck it open. Woodpeckers use them for generations and carry items to them for quite large distances. In this case the bird was lucky, as the source tree of the nut itself happened to offer a good anvil, too. That’s not unusual for walnut trees, which have a very smooth bark on young branches, but a very rough and grooved one on older branches, and which when planted near buildings require regular generous trimming. Where you cut off a branch there is a high chance that over the years an area with ample broken bark is created at the base of the new shoots branching out. Also, such young shoots tend to be weak, bend down over time and rip open on the top side. In general, dead trees, breaks in the bark of living trees, but also has-been-dead-trees-turned-fence-posts are favourites for Spechtschmieden. Here’s what the place looked like after the bird had flown off.

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A typical case for a walnut tree: bottom left you can see where a bigger branch had been cut, and the young shoot was long and thin and directed into the crown (thus received little light – don’t be cheated by the sunlight in the pic; the inside of a densely grown walnut crown is quite dark!), and bent under the weight of its leaves. A tiny tear in the bark on top developed over the course of a few years into quite a large welt, which now can receive one of the small nuts and hold it fixed. It is also entirely possible that the woodpecker improved the quality of the Schmiede by removing some wood and bark to make it larger.

I’ll end this with a more typical perspective of a woodpecker: up into a tree with the bird theropod sitting on the stem. This one I took right in our front yard, where the artificially increased elevation of the yard versus the tree’s base plus the fact that statistically, there’s practically never anyone moving in our yard meant that the bird let me get very close. The situational awareness of many birds is quite astounding; they have a pretty good feel for what’s normal and what’s not normal and might mean a predator sneaking up on them! For example, the birds in our hedgerow will completely ignore us, grandma, our neighbours and our neighbours’ dog, but fly off immediately when a rare visitor like my parents come into the yard. This woodpecker quite clearly considered me and my approach route as mostly harmless, whereas a women coming down the sidewalk got it to fly off when she was still three time as far away as I was.

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Posted in anatomy, Aves, Dinopics, Dinosauria, Maniraptora, photography, Theropoda | Leave a comment

Measuring Giraffatitan’s limbs

TL; DR: loads cool pics of dinosaurs at end of post.

Recently, a colleague contacted me via email. He wanted to know if he could use the opportunity of his Berlin visit for SVP to climb up a ladder and have some fun with a tape measure and the limbs of Giraffatitan (ex Brachiosaurus). He was interested in the minimal shaft circumferences of humeri and femora, from which one can calculate a rough estimate of total body weight (see here). That’s been done for Giraffatitan, but apparently it all traces back to a personal communication from ages ago.

Well, access to the mounted skeleton is difficult under the best of circumstances. The platform the skeletons in the MfN’s Dinosaur Hall rest on is covered by a roughened surface that is rather delicate, so you can’t simply walk all over it. And walking in socks can be quite uncomfortable. And that is the least of your worries, if you want to access anything above elbow/knee level: Giraffatitan is rather tall, but placing ladders close to the skeleton is not that easy, given the touchy surface and the fact that there are railings and other skeletons and whatnot around it.

Additionally, the museum is open all week except Mondays, and we do not like having people climb all over the exhibits during visiting hours. Simply so that we do not give our museum visitors stupid ideas……. So you’re either limited to the early morning and late evening hours – if a curator is willing to come in really early or stay really late. Or you can show up on a Monday (obviously pre-announced) and have all day. Not just any Monday, though – occasionally, the museum is open to the public on Mondays, too. This was the case for the two weeks this fall due to school holidays.

Now add SVP to that (the annual meeting of the Society of Vertebrate Paleontology), with some 1300 crazy vertebrate palaeontologists descending on Berlin, and the corresponding demand to see the collections in the week before and after the meeting….. yes, there are quieter times to get into the Dinosaur Hall than those two weeks this fall. And the SVP meeting week’s Monday happened to be the first Monday after two weeks of the museum being open, which means that it was the Monday the cleaning crew really needed to get in there. Oh, and by sheer luck, it was the Monday on which an orchestra had the hall for a rehearsal for a concert later that week. It never rains, but it pours.

So, the Monday right before SVP was a total no-go. I couldn’t help my colleague either, even though quite obviously there is a bit more wiggling room for employees than for externals. But even if there had been a short time window for me to access the skeleton with a ladder, I was busy as hell with other stuff – SVP in Berlin meant colleagues coming over, and two came over early whom I really needed to sit down with and talk fossils. More about that later; it’s cool stuff we work on together.

However, when I mentioned the cleaning crew, I talked about the regular dusting and mopping. There’s more to keeping the Dinosaur Hall clean, including a yearly window cleaning. Yes, yearly is enough, because all the windows are indoors windows, in the walls between the Dinosaur Hall and neighbouring exhibition and collections rooms. But to access them one needs a lifting platform, a hydraulic hoist. And – guess what? – the annual window cleaning was up for the Monday after SVP. And the window cleaner is a really nice guy who doesn’t mind sacrificing part of his breaks in order to lift a crazy palaeontologist or two up into places they normally can’t get to.

So the next Monday, while I was horribly busy already managing (link to German news video) the Fraunhofer IDG automated 3D scanning test at the MfN, my colleague Matteo Belvedere and I used the lifting platform to get some measurements of the limb bones. And we used the opportunity to also take a lo of photos of the dinosaurs from viewpoints you usually can’t get to. Previously, I had used a ladder or took photos from 1st floor windows, but this was MUCH better :)

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Two photos of me in action, both taken by Matteo Belvedere. Later, we switched roles with him up there and me on the ground, running off to run the CultLab3D thingy.

So, what about getting tight and cosy with Giraffatitan? Below you can see Matteo with the humerus, which was marked with tape in the three places we measured. While he was up there measuring I was standing ready to make notes. Note the scale bar we fixed to the vertical strut! Once I finish the photogrammetric models we can use this 1 m bar to scale them correctly.

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Obviously, we now need to do some really hardcore science with that stuff, too – for now, I’ll just show you some of the pics we took.

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A pterosaur’s view of Dicraeosaurus, slightly anterior. In this view it is really clear how 2D the sauropod is: it is high, it is long, but it isn’t wide!

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A view from further away and to the left back. Note how the narrow silhouette get additional height from the tall neural spines.

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And a look along the side of the back, showing off those spines to full effect. Giraffatitan‘s puny ones in back.

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Riding Diplodocus this is the view you’d get at your 12. Note the used and unused rings for hanging the neck from the ceiling – obviously they are not supposed to take the full weight, but only part of it – and in the process dampen any oscillation of the neck in case it gets bumped.

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Reverse view.

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A bit further back you can see the entire trunk and neck. As with Dicraeosaurus, this view highlights the extreme length versus a very reduced width. A legged snake? Not that far off.

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Over to fat-bellied Giraffatitan! The wide transverse processes of the dorsals make this animal look like a snake on legs that just had a huge capybara for lunch. Or, rather, an entire elephant.

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A closer view…..
and now for something completely different:

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Tiny spiky Kentrosaurus! It is so small that a 4 m high ladder allows taking similar pictures. Thus, enough with ornithischians already, back to more chunky stuff:

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Better! This view puts the nasty bird-hipper into the correct context with regards to dinosaur size! Yes, you can see that Tendaguru’s monster hedgehog – capable of 60 mph strikes with it’s 8x-basball-bat-weight tail tip – is not even half as long as the tail of Diplodocus. But then, isn’t it the tiny dogs that bite, making up their puny size with extra aggression? ;)

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In fact, some sauropods did not have such huge, long tails! Check out the tail of Giraffatitan compared to Dicraeosaurus‘ and Diplodocus‘ tails and (part of Kentrosaurus) in this pic! It is still much longer than all of Kentrosaurus, but compared to the more regular, short-forelimbed and level-backed sauropods around it Giraffatitan has a short and slim tail.

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Here, you can appreciate that it still is quite a significant tail. But compare the width of the tail to the width across the hips and across the middle of the trunk. Much slimmer tail than either Diplodocus or Dicraeosaurus. In fact, it looks almost mammalian, somewhat similar to a kangaroo or even less substantial.IMG_9849_sm

To reiterate those points on narrowness of the trunk and ratio of tail to trunk width, here’s a view along the trunk and tail of Dicraeosaurus, taken from nearly directly above the neck base. See how the tail base is actually wider than the width across the tops of the ilia?

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And more fat Giraffatitan rump. This view is really weird, but it does show up three things quite nicely: the wide back, the narrowness of the neck and the U-shape of the shoulder girdle.

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Wwith the left forelimb in view you can’t see the back as well anymore, but the abrupt vertical front end is nicely on show. Compare to the horizontal orientation of a diplodocid – the long-armed, tilted-back sauropods are really weird!

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A bit higher up we can get a total view. The perspective distortion makes the head look not ridiculously small as it really is, but it does highlight the stick-like neck.

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OK, wrapping up with a portrait or two:

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antero-lateral and very slightly ventral from the left and

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lateral and very slightly ventral from the right. Say cheese!

 

Posted in 3D modeling, anatomy, Conferences, Digitizing, Dinopics, Dinosauria, Giraffatitan, MfN Berlin, photogrammetry, Sauropoda, Sauropodomorpha, SVP 2014 | 9 Comments

SVP2014 – the wind-up

Today is Sunday, November 2, 2014, which means that the 74th Annual Meeting of the venerable Society of Vertebrate Paleontology will start in less than 72 hours. Hashtag #SVP2014, by the way. Depending on how you count the public lecture on Tuesday evening, things start day after tomorrow in the evening or one day later – at 8 a.m.!

As is usually the case, the last minute preparations are crazy, but this year the crazy is extreme. SVP comes to Berlin, and I am on the Museum für Naturkunde’s Host Committee. That’s added stress to the usual, with the latter being two posters (one as first author, one as second who has to do most of the work due to our division of labour on the project). The first is finished, the second still in the making. Ugh! But both posters deal with cool stuff, and I am very much looking forward to my colleagues’ reactions. Obviously, I’ll post about both here, too.

What else will be up this week? For one thing, EVA Berlin 2014! Where I will give a talk on Wednesday morning (yes, ideal timing *sigh*) on how a lack of standards for documenting how you 3D-sscan something means that nobody documents anything, which invalidates many 3D-models for research. Ugly topic, and I hope my talk will be a sort of wake-up call for many players in the field.

And then, obviously, there will be a bit of free time to talk to all those many friends and colleagues I only see sporadically. And there will be beer, and dinosaur talk, and anecdotes about crazy professors, crazy students, crazy excavations – i.e., there will be vertpalaeo-fun :D

So, back to poster making…. here’s a sneak preview.

tail recon

Photogrammetrically derived 3D model of the tail of Citipati osmolskae with partial muscle reconstruction.

Posted in 3D modeling, Berlin, Citipati, classic CAD, Conferences, Digitizing, Dinosaur models, Dinosauria, Maniraptora, Oviraptorosauridae, photogrammetry, SVP 2014, Theropoda | 3 Comments