Photogrammetry with a macro lens

So far, most of my photogrammetry efforts have dealt with specimens in the several centimetre to meter range. Bones, skulls, entire skeletons. The smallest models I created were of ammonites – more on that currently on-hold project later – with diameters of several centimetres. “several” here meaning more than 4, i.e. 40 mm. That’s a range where my kit 18-135 mm lens is hard pressed at the lower end, because the specimens are so small on the image that the alignment in Photoscan often fails unless I let the program use the image background. And that causes further bother later on if I need to digitize a specimen in 720°, as I call it: 360° around horizontally, and also all around (another 360°) vertically – a specimen that I want to capture the “bottom” of, too. In contrast, a specimen embedded in rock would be only 360°, because I do not wish to digitize it from below.

If now a specimen makes up only a small part of each image, its surface isn’t well resolved in them, and Photoscan is hard pressed to find features to correlate with other images. That means that I can’t just mask the background out of all images and toss them all into one chunk for alignment, because the angle difference between many images will be too big for Photoscan to work it out based on few matching points.

Quite the obvious solution is the use of a macro lens. Which requires having a macro lens. And that’s as far as I got – until Wednesday! Here’s how I got by a macro lens and what I did with it:

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Posted in 3D modeling, Conferences, DigitalSpecimen 2014, Digitizing, photogrammetry, photography, plants, raves | 1 Comment

How to easily de-conflict event timings for conferences

Today’s topic has nothing to do with dinosaurs, but it is something some of you may encounter every once in a while. Let’s say you’re planning a conference with many events – talk sessions, poster sessions, workshops, whatnot. Obviously, you’ll ideally time all events so that everybody can take part in all events they want to. However, it is usually not possible to have only one single session at any one time. As soon as you have dozens of people attending you’ll end up with more events than time.

So now, you’d ideally find out who wants to attend which events, then find the combination of timings that reduces collisions to a minimum. But how to do that? How do you find out which potential collisions occur least often?

I am facing this problem right now for the DigitalSpecimen 2014 conference, where up to 100 people may wish to attend up to 8 workshops each. Here’s how I solved the problem with a little very primitive EXCEL magic.

1. Polling the attendants
I asked people to register for the workshops they WANT to attend. I assume that they all answer truthfully. Thus, I know who wants to attend what combination of events, i.e. which events should not be at the same time for that person.

2. Hacking the data into EXCEL
I now made a table in EXCEL where each line is for one attendant. It has one column for each workshop. I enter a “1″ if the person registered for the workshop, and a “0″ if the person did not register. This is what things look like now:

Excel_01

Don’t mind the gap – I only use it to separate MfN employees from the rest. Sums and all work across gaps, too.

3. Computing collisions
I now added further column, one each for each possible conflict. Thus, I no have columns titles 1/2, 1/3, 1/4….. 2/3, 2/4, 2/5…. 3/4….. and so on. (Remember to format the cells as “text”, otherwise the program will turn these entries into dates or whatnot!)  Now, I enter formulas into the cell from the row with the first attendant: =PRODUCT(Cell1;Cell2), with Cell1 the cell that holds the info for that attendant on the first of the two possibly conflicting workshops, and Cell2 the info on the other one.
If the person registered for both workshops, the result obviously is 1*1=1. If she or he registered only for one or for none of the workshops, the result is 1*0=0 or 0*1=0 or 0*0=0. Thus, if there is a potential conflict, the result is 1, if there is none the result is 0.
Now, I know which collisions occur for the first person whose data I entered. By pulling down the bottom right corner of the field across all rows that hold names I can make EXCEL apply the same formula for all of them, and quickly have the info for all attendants.

4. Summing up collisions
To find out how often each collision occurs, I now add a row of sums at the bottom. Under each column of 0s and 1s (for no collision and collision) I enter =SUM(Cell3:Cell4), with Cell3 the top-most data cell in the column, and Cell4 the last one. And presto – I get a nice row of numbers that tell me how often each collision would occur for a given pair of workshops.
Here’s how that looks:
Excel_02

And now, I can see at a simply glance which events I can place at the same time without pissing off too many of my esteemed colleagues, and which pairings I better avoid! In this case, Workshops 1, 3, 5 and 7 should all be planned to not run in parallel, whereas a WS 2 – WS 8 collision would hurt only few people.

 

Posted in Conferences, DigitalSpecimen 2014, How to, non-palaeo | 1 Comment

A digital dino bone

This post is a re-blog, or more accurately the English translation re-blog (with minor alterations to adapt it to pre-existing content here on dinosaurpalaeo), of a post I wrote for the Museum für Naturkunde Berlin‘s blog Museumsdinge. The title roughly translates to “museum things/objects/topics” – as often, there is no one-on-one corresponding translation between German and English.

The bone in the image below is nothing extraordinary, really, at least not in a natural history museum. The left thighbone of a dinosaur – so what’s special so about it?Still, this is no ordinary dinosaur! And what is that red stuff on it?

Kentrosaurus femur digital model

You won’t find this dinosaur in a lot of museums. First of all, because the dinosaur in question, Kentrosaurus aethiopicus Hennig, 1915, isn’t present in many collections. Only in the Museum für Naturkunde Berlin and the Palaeontology department and museum, Institute for Geosciences, Eberhard-Karls-University Tuebingen (homepage) can you see a Kentrosaurus.

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Posted in 3D modeling, Berlin, Conferences, DigitalSpecimen 2014, Digitizing, Dinosauria, Kentrosaurus, MfN Berlin, Ornithischa, photogrammetry, Stegosauria, SVP 2014 | 3 Comments

China 2014 part 1

My colleague Michael Pittman is a young, ambitious and smart researcher who has done some very nice work on tail stiffness in archosaurs. Now, Michael has a grant going for a project that expands on his previous work, and there are a lot of big names on the grant along with him – and I am on it as well! Not because I am one of the bigshots (most certainly not), nor because I know much about tail stiffness in archosaurs, but because I can build nice research 3D models in a variety of programs, including the necessary 3D digitizing. Previously, I collected data at the AMNH for this project. And in February it took me to China two weeks ago.

Michael and I wanted to check out some fossils in this place: the famous IVPP.

china_01
Pics taken from my hotel room; the XiYuan hotel is a very good place to stay and IVPP visitors get a very reasonable rate.

The IVPP is a research institute, and I’ll have some thing to say on that topic later, but it also has a museum part. For reasons that will become apparent in due course my visit to that museum was rather short and somewhat strenuous, and I have little to write and show. Let’s get this over with, and then advance from the holiday part of my trip to the work aspects.

In the center of the main room of the IVPP museum there is a big pit that houses a number of dinosaur mounts. Here’s a hapless Tuojiangosaurus multispinus having a very bad day at the hands… erh, teeth of Monolophosaurs jiangi (thanks, Dave Hone: I forgot to take a pic of the label of the latter dinosaur, but your photo of the two mounts includes it).

IVPP_02

Of more interest to me, given my history of involvement with plateosaurid dinosaurs, is this critter below: Lufengosaurus!

IVPP_03

OK, looks rather clumsy. The dinosaur below is much nicer:

IVPP_04

Sinornithosaurus millenii. Fluffy! :) It was really cool to see this really famous specimen.

Now, work. What took me to China this year was Michael’s rather cool project on oviraptor tails. But as I happened to be at the IVPP anyway, and as my esteemed colleague Jingmai O’Connor had suggested that I give a talk on photogrammetry there, and as there actually was a time window that allowed me to give that talk, and as my famous colleague Xu Xing at the IVPP actually managed to arrange things……

IVPP_01

… I did give a quick intro to a rapid and cheap 3D-digitizing technique. The announcement, above the one that hung in the elevator, suffered a bit from being copied from what I jotted down for Xu, who apparently had some trouble reading my admittedly horrible handwriting. But the presentation was a success, with the listeners (palaeontologists and archaeologists alike) becoming increasingly interested instead of nodding off to sleep – always a good sign!

Michael and I studied a number of specimens I can’t show you, because they are not on exhibit, but I can show you one that is on exhibit in the National Geological Museum (homepage if you read Chinese) in Beijing. The specimen is labelled Shenzhousaurus orientalis NGMC 97-4-002, and it is shown in a glass-covered steel-cornered box. Very safe, which is good. Although I hate when exhibits are behind glass because it makes seeing and especially photographing them so much harder, it is much better to have them behind glass than damaged or stolen. And too many museums, the NHM London and the MfN included, have had dinosaurs on exhibit pawed and fingered and broken by the unwashed masses. In this case, I would have done things a tiny bit different with regards to the lighting, but then, I always have photography and photogrammetry on my mind, whereas museum exhibit planners have other priorities, mainly the dramatic impact.

Shenzhou01

Shenzhousaurus orientalis type specimen with calipers for scale. Note the blueish light stemming from a neon tube mounted inside the glass cabinet.

So, I set to photographing this small precious raptor, which was a bit of a bother because of an unfortunate meeting of my left knee with the Beijing sidewalk asphalt the day before (the reason why my IVPP museum visit was not that much fun, and short). Suffice to say that I felt very House-ish limping through Beijing and through the Geological Museum (a place well worth an extensive visit!) on my crutch. I was, however, capable of handling my camera and tripod quite well. Here’s a glimpse at the results of ~5 minutes of photography.

geol inst

As you cannot see in this screenshot, the model came out quite nicely, although not quite perfect. I blame the dust on the inside of the glass for some imperfections – and I can’t get rid of that horrible colour!

 

 

 

Posted in "Prosauropoda", Dinopics, Dinosauria, Hadrosauridae, IVPP, Ornithischa, Sauropodomorpha, Theropoda, Travels | Leave a comment

A wonderful Plateosaurus drawing

Currently, I am horribly busy and thus not able to blog much. But here I have something that I must show you, now that I have finally managed to scan it.

PlateoDrawing
click for larger size

Last fall I received this wonderful drawing of a Plateosaurus stealing my birthday cake from none other than Himmapaan (Niroot Puttapitat), a exceptionally gifted (and extremely diligent and thorough!) artist – find more of his work here on his blog and here on deviantART, or here on Facebook. He is also a very modest and friendly person, as I found out when I had the pleasure for visiting the London Zoo with him.

As you can see, the Plateosaurus above is not only properly muscled and proportioned (and appropriately bipedal), but also meticulously drawn in tiny detail. Oh, and the dragonfly that tries to hide away on the top left is gorgeous, too! Every time I look at this wonderful picture I can’t pull away and study the minute details afresh.

What a wonderful present – thank you very much, Niroot! It gives me great joy every time I see it!

Posted in "Prosauropoda", Dinopics, Dinosauria, Plateosaurus, Sauropodomorpha | 4 Comments

Photogrammetry tutorial 6: building a model from the photos

We’ve been through the details on how to take photos for photogrammetry (parts 1, 2, 3, 4, 5), now it is time to talk about the next step: how to actually get a program to build a model for you.

For all those who wonder why there are no pics in this post – patience, young Palaeowan! There will very soon be a paper out that has all the info and pics you need, and that’s all I will say now :)

There are plenty of photogrammetry programs out there (see this overview, somewhat incomplete, on wikipedia), some of them for free, some of them looks like they cost nothing, and some that cost money.

Why do I say some ‘look like they cost nothing’? Because some cloud-based programs actually do not cost money, but want the copyright to your models, and some even to the photographs you upload. Quote from Autodesk 123D Terms of Service: “… you grant to us and our affiliates a world-wide, royalty-free, fully paid-up, perpetual, non-exclusive, transferable, and fully sublicensable (through multiple tiers) right and license (but not the obligation) to reproduce, distribute, redistribute, modify, translate, adapt, prepare derivative works of, display, perform (each publicly or otherwise) and otherwise use all or part of Your Content, by any and all means and through any media and formats now known or hereafter discovered, but solely in connection with the Service and/or our business activities (such as, without limitation, for promoting and marketing the Service) and/or to comply with legal or technical requirements.” Obviously, they need rights to do much of that so they can actually use your raw data to make a model for you, but look at the bolded parts! Imagine you create a really neat model of something, and Autodesk distributed printed-out copies of it as an advertising gift to millions of people……. That’s a minefield you should NOT get into!

Personally, I use Agisoft’s Photoscan Pro. An educational license costs $549, and the program covers 99% of my needs, while being extremely user-friendly. Also, I have made excellent experiences with the Agisoft support team, via their user forum, so overall I am very happy with my choice. Others tell me that the professional Autodesk program Image Modeler  is excellent, too, and it contains a lot more than photogrammetry capabilities. On the other hand, VisualSFM (SFM = Structure from Motion) is completely free for personal, non-profit or academic use, and gives you many options for handling difficult data sets that Photoscan Pro doesn’t have. My esteemed colleague Peter Falkingham is a great fan, and has used it successfully for some very neat science work, including the reconstruction of the Paluxy River trackways from old photos. Peter also has a neat guide on how to use VisualSFM and the free mesh editor Meshlab up on Academia.edu, so if you’re registered there, go grab it.

So what you read below is what I do in Photoscan, and if you use a different program you may need to adjust things a bit to the specifics of that program. The general principles, however, hold true for all of them.

Alignment and Model Building

Before I give you details on what to do in-program, it is important to know what kind of raw data set you have, as directions differ a bit.

Immobile specimens

If we’re dealing with an object that you could only photograph using the walk-around method, you should simply throw all the photos into one Chunk in the program, and run Alignment*. If the resulting sparse point cloud (a point cloud consisting of all the points the program used to find the camera positions) and camera positions look fine, the next step is generating a dense point cloud. You now have two options: have the program build it, then clean it up by removing the objects around your specimen, or mask all photographs to remove the objects around your specimen, and then have the dense cloud calculated. Usually, the former is more difficult, while the latter takes longer. If I need to do a lot of pre-alignment masking, or if I want to be very sure that the final model will have perfect edges where the real specimen contacts its support, I opt for masking first. Otherwise, I often choose middle ground: I mask all photographs, but only where the specimen contacts the ground. That gives a nice distance there, to use for cropping the dense point cloud.

* Remember that if there is motion in the background, like people walking through, you will need to mask the moving objects on all photographs they appear on!

So, decide how to proceed, mask as necessary, align the photos (Menu ‘Workflow’, option ‘Align Photos’). Now adapt the selection box as needed (sometimes, the auto suggestion will cut off part of the specimen), and have a dense cloud built (Menu ‘Workflow’, option ‘Build Dense Cloud’). Crop that dense cloud as needed and have a mesh built (Menu ‘Workflow’, option ‘Build Mesh’)

Turntable specimens

If you used a turntable for the photography, you will likely have to mask the background in all images. And I assume that you took at least two sets of photos, between which you flipped the specimen over so that you can get a model of the underside, too.

In this case, you can proceed as above, with prior masking or with cropping-after-dense-cloud generation if you treat both series separately, and only combine them into one chunk later (what I term the multi-chunk method; see below on how to do that). However, the most elegant way is having all photos in one chunk, and having Photoscan spit out the complete model in one go. This I call the one-chunk method.

For the one-chunk method, you should always mask all images. If you made sure that the background in your images is out of focus or so blank that Photoscan can’t find any points, it may be enough to mask the ground below the specimen near the contact points – but that may lead to colour errors in the final model. Thus, I recommend spending the time to completely mask the background in all images. Luckily, Photoscan has an ‘invert’ option for the masking tool, so you can simply click the masking line all around the specimen, hit the invert icon, and then ‘mask’.

Now align and see – if your photos are good you should get a perfect alignment! Build the dense cloud, the mesh, scale it (see below) and enjoy! Yes, that simple!

If it is that simple, why would anyone use any other method at all? Well, the one-chunk method has one slight drawback: it depends on you taking really good photographs, that are perfectly suited for photogrammetry, and taking them in proportion to the part of  the surface they show. If Photoscan has a hard time finding enough points in some images, or if there are parts of the surface that are grossly overrepresented in the images, you will end up with a sub-perfect alignment. Or if you can’t really fill the frame of the image with your specimen, which is not that rare when you digitize small specimens with a normal lens. In really bad cases, Photoscan may even be hard pressed to align the photos from one set, and there are ways for helping the program along, mostly using the background for alignment. However, if you do that, you need to have the background immobile versus the specimen (i.e., rotate it with the turntable, e.g. by placing a printed text page on the turntable and under the specimen), and you can’t use the one-chunk method easily.

For the multi-chunk method, which you can also use if you did not use a turntable,you must place each set of images in a chunk of its own. You do NOT want to mask the background that moved with the specimen. However, you should mask a thin strip around the specimen, to create a small gap in the dense cloud that makes cropping the background away easier. Basically, it is the same thing you want to do as with immobile specimens. Now, align the photos in each chunk, check the alignment, create the dense clouds, and delete the background points.

Next come the tricky part: you need to place at least three markers on each model that are in the exact same spots on both chunks. The best way is to place those markers on the photographs by finding a point that you can really nail down to the exact pixel on several shots, right-click on one photo on it, choose ‘Create Marker’, then right-click and ‘rename’ that marker (e.g., ‘A’ or a speaking name like ‘large sand grain on left postzygapophysis’, or whatever). If the marker is not perfectly located you can left-click and drag it.

Now, go to another image from the same set that shows this point, right-click on it, and choose ‘Place Marker’. From the pull-down menu, choose the correct marker. Repeat this procedure until you have three markers placed and visible on the dense cloud, and check that they show up on the cloud where they should be.  This is a good check on how good the alignment within each chunk really is. If your markers aren’t in the right place on the cloud, check your makers on the photos. If that’s all OK, you can’t use photo-based markers and need to switch over to cloud-based ones. These you create similarly, but it is all a bit more cumbersome, as you can’t right-click a marker to rename it, nor can you shift its position with the mouse. And later it will mean that you can’t merge the two dense point clouds into one, but have to calculate a new one from the merged chunks’ sparse point cloud – ugh! So do try to find images that are well-aligned and create your markers on them.

Now, place markers in the exact same places in the other chunk, and rename them to the exact(!) same names. Now, choose ‘Align Chunks’ from the workflow menu, set the method to ‘Marker based’, make sure the correct chunks are selected, and clikc ‘OK’. There is an option that is a bit confusingly names ‘Fix Scale’. It does not, as I first assumed, fix any scale differences between the chunks, but rather makes Photoscan NOT scale the chunks to fit each other. DUH!

Once aligned, you now need to merge the chunks. Menu ‘Workflow’ –> ‘Merge Chunks’. Logically. As I said, Photoscan is very user friendly ;) It creates now a new chunk, so your previous work is untouched. You will want to merge the models, so tick that box. Do NOT tick the box for merging markers, as un-merged markers are an easy way of spotting problems. Now, check out the merged dense cloud in the new chunk. If the marker pairs are very close together and the cloud looks fine, have a mesh generated and you’re done. If something big is amiss, it is usually caused by erroneous marker placement. Delete the merged chunk and fix, then align the chunks anew and merge them again until satisfied.

Scaling the Model

This last step should be easy, provided you followed the protocol and added a scale. All you have to do is mark the ends of your scale in at least two photos. In Photoscan, you right-click in that place on the photo, choose ‘Create marker’, and then rename it (e.g., 0 cm or 3.7 cm or whatever; it is usually smart to use a speaking name!). Then, choose another point and create a second marker, and rename it (e.g., 10 cm or 7.2 cm). Try to use the longest distance between markers you can find!

Now, go to another image and find the same points. Right-click, choose ‘Place marker’, and select the correct marker. Doing so in one other image will do, and you do not even have to create and place the two markers in one image each. You can place one marker in, say, your 5th image, another in your 8th, and place the first on image 3 and the second on image 11. Doesn’t matter, as long as the scale object you used hasn’t move relative to the specimen between all those photos.

Once you have the two markers, select them both (CTRL and left-click one, then the other), right-click and choose ‘create scale bar’. Switch to the Ground Control tab (at the bottom left!), select the scale bar and enter the length for it. CAUTION: Photoscan is in meters! Now, click on the ‘Update’ icon on the top of the pane (it looks like two blue arrows forming a circle). DONE!

 

 

 

Posted in Digitizing, photogrammetry | 1 Comment

Adolf “Dolf” Seilacher, the Grand Old Man of trace fossil analysis, has died

Last week, one of (or arguably the) greatest palaeoichnologist, Adolf Seilacher, died at the age of 89. I met him only rarely, and had little professional interaction with him, but that little makes me mourn his death more than I would mourn most other colleagues, even many that I worked or work with closely.

When I was a young student goofing off at Tübingen University I was lucky to have many excellent professors, luminaries in their field. Adolf Seilacher, however, stuck out in many ways, although he was rarely present: “Seili”, as German students called him behind his back, had retired before I even enrolled, but like many of his colleagues he would never stop being a researcher and teacher. Although he spent much time on Yale and in the field, he usually taught a compact course in Tübingen every second summer, and one year I was able to attend. The course was on trace fossils, Seilacher’s main research area, but instead of “Trace fossil analysis” (or whatever the actual German title was), it should have been called “How to be a good scientist, on the example of trace fossils” or some such.

I’ll have some more to say about this course later, but first let me tell you about Seili as a person. From spring through fall, everybody in the building always was aware of his arrival, because he invariably arrived on his trust old Vespa. I do not know how many he owned in succession, but given the work-out he gave them there must have been many. Over the course of the trace fossil analysis course and various conversations I had with him over the years there were quite a few stories, all research-related, that included “mei Veschpa” (yes, he had quite a Swabian accent). It all started, I gather, when as a young grad student or freshly promoted doctor he did not have the means to travel by car to sample the Pyrenees for trace fossils. So he packed as few personal effects as possible, loaded his Vespa with himself, his wife and a backpack that “threatened to work as an involuntary friction brake on the rear tyre”, as he put it, and set off. The narration was accompanied by a hilarious pantomime of the vehicles leaning on slopes up and down. As with many other stories, I am sure some embellishment was involved – but as I came to realise very quickly the embellishments were never meant to increase Seili’s prestige, but rather to drive home the lesson more forcefully, usually via humour. All of these lessons, and nearly every story had one, were delivered with boyish enthusiasm and twinkling eyes, had little to do with being a conforming scientist, and more with being an independent, active, diligent and resourceful inquisitive person. Much, however, was often left unsaid, and it could take me a while to figure out what exactly the central message was.

The funniest and certainly weirdest story Seilacher told us was that of a field trip to the deserts of western Egypt during which a neighbouring research camp was raided by Libyans, who abducted a young American researcher. The poor man was quickly and unceremoniously set free again at the door of some US embassy in Northern Africa, IIRC, and Seilacher thought no more of it for a few years. Then, he was accosted at a conference by a young man he had never met before, as far as he could recall, who stepped up to him and said words to the effect of “great talk – by the way, you’re the man who got me abducted!” It turned out that the Libyans had intended to abduct the world-famous Yale & Tübingen professor, and by accident driven to the wrong camp, abducting an insignificant PhD student instead of Seilacher. Seili concluded the story by remarking dryly that this encounter made him think twice about the personal invitation letter from Muammar Ghaddafi for a research stay in Libya! Needless to say, he didn’t go.

Another story, one that he repeated twice during the one-week trace fossil course (which already tells you that its lesson is important) was that of another meeting with a colleague at a conference, who tore into Seilacher’s just-given talk on trace fossils from some site in Jordan or Morocco or so (sorry, the message got across so well that I forgot the details). The colleague informed Seili that he had been to the very same rock exposure the summer before and had found plenty of trilobite body fossils, which Seilacher said didn’t occur there, but nary a one of the trilobite traces (Cruzianas) that Seili had talked about. He must, insisted the colleague, have mixed up the cliffs and formations! Seili, on the other hand, was quite adamant that yes, he was quite able to read a map, thank you very much, and that he was quite sure of the place and formation. The two of them parted with the conflict unresolved, but with an agreement that would allow a solution to be found a while later: that they would meet there and check out the place together. When they actually managed to make the joint field work happen, they found that they had indeed been talking about the same place. Now, one went left, the other right, to hunt for fossils. Thirty minutes later them met again. Unsurprisingly, Seilacher’s backpack was full of trace fossils. However, his colleague had a backpack full of trilobites! Having seen each other’s spoils, they now changed sides – and golly, the place was indeed full of both body fossils and traces! Lesson learned: collection bias is much stronger than even the most experienced researchers will be ready to believe!

Seili had many idiosyncrasies that make for great story-telling, foremost that one could never know if he was being serious, or making an important point in an elaborate way – or simply pulling one’s leg! A certain playfulness and sense of humour also pervaded his scientific work, most notably expressed in some of the species epithets he coined. Asteriacites gugelhupf is a track made by a suspension feeder from the Carboniferous of Egypt, the bilobed scratch pattern of the upturned arms suggests an asteroid rather than a brittlestar. Seilacher named the trace, because of its similarity in shape, after a cake that is a favourite for birthdays in Germany. Such names that were driven by everyday connotations and associations crop up quite often in his works, as well as other versions of “speaking names”. To Seilacher, science and everyday life were not separated, but one, and while some may see some of his work as science outreach, to him it was just natural, and communicating science to non-scientists came natural to him.

Others way more qualified than I will have much to say about Seilacher’s scientific work, his impact on palaeontology and ichnology, his Crafoord Prize and so on. I’ll just quickly note a huge part of his life effort that falls squarely within the outreach category, and has had a profound impact on the perception of palaeoichnology: the Fossil Art exhibition. This travelling exhibition takes casts of trace fossils and presents them as if they were works of art – accompanied by short texts succinctly explaining what they are. The overall presentation always has the character of an art exhibit, and Seilacher and his collaborator, Tübingen preparator (or should I say preparation magician?) Hans Luginsland selected mostly specimens with an immedatie artistic appeal. The latest version of the catalogue book for the exhibition is available in German from Schweizbart. You can find (low quality) photographs and details on many of its panels it on this page that accompanied a previous stop in Denmark. The most famous one, I guess is this one with plenty of Cruziana on it.

The show has travelled world-wide, with the last two stops in 2013 having been the ETH Zurich and the Senckenberg satellite in Dresden. As far as I could ascertain, the show has now been gifted to Senckenberg, but I was unable to find out where it will move next. I hope the death of Adolf Seilacher will not result in it being stored and forgotten, as it is a beautiful and striking way of arousing interest for palaeontology, and a branch often ignored and unknown to many at that, in the general public, fascination people of all ages and backgrounds.

But now it is really time to come back to the one Seilacher course I took. Trace Fossil Analysis was held in the summer break, with the lecture hall in the main building of the Institute of Geosciences in Tübingen stifling hot or, windows open, noisy and hot, quickly creating a drowsy atmosphere. Still, most attendants were highly motivated, as was the lecturer. We quickly went through some charismatic and historically important trace fossils, including Hitchcock’s ‘birds’ and, obviously, the Chirotherium story. Then came the first invertebrate tracks, and for some tedium set in. And Seilacher proved to be as excellent a lecturer as I had heard: he’s explain things repeatedly, until everbody had had ample chance to understand things, but didn’t mind that some of the quicker minds blanked out after the second repetition. So once he moved on to the next topic, he always raised his voice slightly to ‘wake’ us all again, before he proceeded, with a smile, with the next weird traces. Sometimes, he could hardly keep from laughing when suddenly, people sat back up who had lain down across several seats while he had been talking with his back turned.

At the end of the course, he gave each of us a trace fossil to comment on, as an oral exam. Given the large number of failures and successes he had seen during his long career, it was very touching to see how he tried very hard to coax a modicum of coherently presented knowledge out of the least gifted and interested, so that he could pass them and give them the coveted “Schein” (Attendance Certificate; grades were irrelevant as they didn’t count into the final grade for the diploma), and how tensely he waited for the replies from the obviously smart and interested – as well as his relief when they did perform well. Seili really cared for every young student who attended, and he understood the strength, weaknesses and motivations of all of them!

Let me end this post before I now get all maudlin. Seilacher will be greatly missed by many colleagues, as the many facebook posts already show. I hope that his legacy lives on in the works of the many students and colleagues he influenced.

 

 

 

 

 

Posted in ichnofossil, Palaeoart, sad news, Tübingen | 5 Comments