1/10 T.rex skeleton

[Thagomizer]

Hello everybody! Glad to have some more stuff to post; it's been a while since I've had the time to work on the wee beastie.

This episode features the hands and arms (again) as I refine the shapes of some of the bones and do a bit more assembly. The bones are being bulked out by single layers of paper towel rolled and pressed into shape and soaked with diluted white glue. This is also used to form the third metacarpal, the small, slightly curved tapering rod attached to the outside of digit II's metacarpal. This has sometimes been called T.rex's "pinky finger" but it is not thought to have been a functional digit as it has no joint surfaces for further phalanges. It was most likely buried in the flesh of the hand, a vestige of the ancestral three fingered condition seen in more ancient tyrannosauroids

The first skeletal reconstructions of T.rex featured three fingered hands, but this was speculation. This three fingered hand can be seen in the first scientific papers by Henry Osborn (see http://digitallibrary.amnh.org/dspace/handle/2246/1464 and http://digitallibrary.amnh.org/dspace/handle/2246/1473) and in the original mounting of the American Museum of Natural History specimen #5027(AMNH5027 see http://www.lindahall.org/events_exhi...b1916b_l.shtml).The discovery and description of Gorgosaurus libratus revealed the didactyl nature of the tyrannosaur manus (see http://www.palaeos.com/Vertebrates/U...a/340.760.html). Hands from T.rex itself weren't found until the early 1990's with the discovery of Museum of the Rockies specimen #555 (MOR555) and Sue. The third metacarpal eluded paleontologists for longer still. Here's an example from a Black Hills Institute specimen called Wyrex:http://www.unearthingtrex.com/media/prep06_arms-hands/

The carpal bones (two little brown specks between the hand and forearm bones) are made from a coloured foam sheet. I picked up the brown "Foamies" sheet at a local art supply store (a tip of the hat to the friendly, helpful and courteous staff at Mercury Art & Crafts Supershop for their assistance) to use for the intervertebral discs but decided it might work for these little scraps of bone too. Foamies come in a wide variety of colours. I can't help but think I might find other uses for them yet. The carpals on my model help conceal the twisted wire used to connect the hand to the ulna and, being flexible, will probably handle the movements at the wrist without coming off or breaking as a harder material might.

The elbow joint is one of my hinges made of thinner cardboard with a section of round toothpick for the pin; the shoulder joint is twisted wire covered in a mixture of glue and paint. I probably won't attach the arms to the scapulocoracoids until the latter are mounted to the completed ribcage, so it's going to be a while yet.

A quick comparison with one of my references lets me tell how things are coming along. Verdict-looking good!

After some final work on shaping and priming the forelimbs I will probably turn to toes to fill and shape them before working out the mechanics of the leg and hip joints.

[Thagomizer]

If any of the more experienced people here could tell me how I change the thumbnail image for this thread in the Forum index it would be very much appreciated. I'd like to have something a bit more T.rex looking than a table of parts and scissors!

Thanks in advance!

[Darkwulf's Talon]

I have to say that this is a work of passion beyond judgement. Well done on your progress so far and if you keep up this level of unrivaled detailing I'm sure the Natural History museums will be knocking on your door with a pay cheque :-)

Though something tells me you would just smile whilst closing the door again, lol

[fealform]

I can´t believe, what I see, simply amazing, and, the chosen material to build it ,just incredible,congratulatios.

[Thagomizer]

So the fingers, hands arms are pretty much complete. One of the fingers on the left hand is a bit floppier than I'd like, but oh well. I can live with that.

[Thagomizer]

I thought that working on vertebrae was bad; they ain't got nothin' on the bloody toe bones! Again careful labeling helps keep things in order from left to right, from toe to toe.

I decided to incorporate the hinge mechanisms into the construction of the bones sooner than I had originally intended so that I could build the toes around them. Working around the finger hinges wasn't as hard as I'd thought so I figured the toes, being bigger, would be easier. I was right. The main part of each hinge was put into the bone closer to the ankle with the next toe bone further away to be attached afterwords. Looking at the pictures might make this clearer than what I'm writing. Frequent checking that each hinge still moved properly after each step gave me confidence that I hadn't glued something that shouldn't have been glued.

Bulking out of the toe bones was with bits of facial tissue or blank newsprint soaked in white diluted glue. Some parts were filled in with pulped tissue (tissue + water + wand style hand-held blender) mixed with white glue. White glue itself was used for refining the shapes of the ungual or claw bones at tips of each of the toes. The photo showing the application shows a bit of a wiggly line between areas of glue. This was repaired a moment after I took the photo but I forgot to shoot the correction!

At one point I forgot to do my reality check comparisons with my drawings and photos and ended up making the distal articular surfaces (the ends further from the foot) too wide and too big. I had built them up too much. (I took no photos of these parts that went wrong. As I said before I'll tell you about my mistakes but I might not necessarily show them!) This was after I'd incorporated the hinge units. After the initial adrenaline rush of panic that I'd irretreivably buggered things up and would have to redo many of the toe bones and hinges from scratch, I had a closer look. All was not lost. I was able to slice these bits off from either side hinge plate and still save the parts. Some of the individual bones are still maybe a tad too long but I can live with them as they are. I had one toe joint go a bit dodgy with the centre hinge plate hole partly breaking through after I had assembled things. I fixed this with a loop of paper strung in behind the hinge pin and glued to the centre hinge plate. The toe hinges are much sturdier than the fingers. Most of them have retained a good degree of stiffness. None of them are really loose and floppy. YEEAHHH!

A coat of paint really lets me see what needs more work. It's easier to find surface imperfections with some sort of primer coat, particularly when you're working with a variety of materials at once, some of which are light in tone, some of which (white glue) dry translucent or transparent. Paint also gives a better idea of what the finished look will be. Looking good, if I do say so myself. There are still a few things to fix on the toes. Some of the shapes need to be refined a bit. This will be done by carefully adding tissue and glue or glue alone. I might also have to do some very fine cutting to improve the range of motion of some of the toe joints, particularly on digit II (the toe making ground contact which is closest to the body centre line) as these should extend (bend up) more than they do right now. I'll know better once I have the metatarsals (long foot bones) built.

[lilalex]

Love the updates, Thag' - and the dino info expressed in each one as well!!

Keep it up, the sculpt is looking awesome!!

la

[Thagomizer]

Here's a layout of the parts so far. Still not represented at all are the lower jaw, cervical ribs, gastralia, metatarsal I and metatarsal V. Once again, Amber provides her service as a scale bar. Fortunately she has not (yet?) developed any taste for dinosaur "bones".

Taking a bit of a rest from limbs and digits, I've gone back to the back. Yes it's the wonderful world of vertebrae! I'm using pulped facial tissue/paper towels for bulking out the centra or "spindle" parts of the verts and papier mache strip for the neural spines. These applications take several days to dry. The whole bone gets a bit damp and soft as the water spreads throughout the cardboard under-structure so however tempting it is to keep working on them it's not a very good idea.

[TitusCrow]

eek! I feel exausted just looking at this and the work involved. Amazing work, a true labor of love. I cant wait to see it finished

[yoitisi]

You're crazy, dude...in the best ways possible. Great project, a true inspiration to see how you pay attention to the smallest details and the overall study of the skeleton here. I love it

[KoTer]

Hi,

This looks very nice! I really like the way you use the cardboard structure to get everything in place. Can't wait to see the final result

[lilalex]

What you're doing with the just the simplest of materials and methods is amazing.

Loving the work - and I look forward to a step-by-step on how you made that realistic fur-covered cat. It looks SO real!!

la

[Thagomizer]

Thanks Titus, yoitisi, KoTer and lilalex! Having an audience really helps so your feedback is a real boost that is one of the things that keep me going, even if you do keep calling me crazy!

Oh, and the cat fur? Easy; just input cat food and the fur comes grows all by itself. Getting the fur to STOP, however, not so easy.

[Thagomizer]

More fun with vertebrae!

This is the dorsal series I'm working with this time, the vertebrae between the neck and the sacrum/pelvic girdle.

In a project such as this there is inevitably going to be a lot of anatomical terminology involved. It might not be necessary if I were just building this on my own just for myself, but in describing what I'm doing to others such as yourselves it does help to have terms other than "the thingy just above and behind the whatchmacallit". The anatomical descriptions used in technical papers start to make more sense the more of them you read. Comparing the text to the photographs and diagrams does let you get the hang of things and see how various structures change from bone to bone through the different limb and body systems. I've picked up a lot of the terminology in the course of building my wee beastie, a bit more with each new skeletal part I work on. It's really not that different from nautical or aeronautical terminology, except there seems to be a lot more of it. Familiarity with the terminology also makes it easier to research specific aspects of anatomy. On several occasions I have e-mailed paleontologists to ask questions about their work pertaining to what I'm doing. Using the precise terms helped me to narrow my request to the particular aspects I was interested in, saving their time and mine. So embrace the jargon, it is your friend!

The buildup of the vertebral structures has been a complicated (and apparently interminable) process. Once the various bits and peices are finally all in place each completed vertebra understructure will be built up with a combination of papier mache pulp and strips.

The major structure being added in this installment is a support found along the underside of the transverse process called the centrodiapohyseal lamina. I suspect that it is a buttress of sorts to support the additional weight of the ribs which attach to the rear extremity of the transverse process. Again a reality check comparison with my reference material helps keep things the right size and direction.

Some of Sue's vertebrae suffer from postmortem distortion that arose during fossilization. This is most evident in the front or rear views which show the resulting asymmetry in the angle of the transverse processes between the left and right sides. The correct angle was determined by looking at other specimens and less distorted vertebrae elsewhere in Sue's dorsal series.

I've also figured out how to do another little bit, the lower point of attachment of the ribs to the centrum (main spool-shaped cylindrical part) of the vertebra. This little bit is called the parapophysis. I'm using a slice of rolled paper tube, slightly squashed to make a teardrop-shaped cylindical piece which will be glue in place at the appropriate time. I've indicated these bits in one of the photos below using little red arrows.

Still to come are the articulation surfaces called the prezygapophyses and the postzygapophyses (either of which is worth several million points when used in a game of Scrabble). Onward and upward!

[lilalex]

More fun with vertebrae!

I have to admit - your and my idea of "fun" couldn't be ANY more different!

Totally blown away with your attention to detail, T - truly inspirational.

Keep up the great work on this - can't wait to see it finished! Who am I kidding? I'm fascinated by just one of your T-Rex Toenail updates!

la

[Thagomizer]

I suppose it’s about time I thought about how some of these bits and pieces are going to go together. Central to most of the structures of the T.rex skeleton is the sacrum and pelvic girdle. In the front of the sacral vertebrae are dorsal verts; behind lies the tail. On either side are the femora. While the exterior shell of the sacrum/pelvis is going to be made of paier mache, inside will be a nice, strong block of wood into which the various other vertebral and limb bones will be plugged. The verts will use wire, the legs dowels. You can see how it’s going to go together in the diagrams.

Still figuring out how the hip joint will work; after some experimentation I’m not so sure the ball and socket joint derived from animation armatures is going to work out. I’m not sure I can build it to be stiff enough; if it loosens over time I’m not going to be able to tighten it. I think I’m going to have to go with something simpler and more robust. To top it off I can’t get my mechanism as designed to actually fit inside the shell of the femur! I’ll go into more detail in a future update.

It just so happens I have a suitable piece of wood around. It’s a piece of hardwood (type unknown) 3/8” x 3/4”. I cut it to the desired length and cut a couple of smaller pieces to add on the top side to receive the vertebral wires. These are pinned into slots notched into the larger piece. This is easier than getting a larger piece of wood and carving it down. A hole is drilled to accept the dowel that will mount the femora. This is sealed with diluted Weldbond to keep out the moisture that will accompany the papier mache construction to follow. Toothpicks are used to attach the neural fused spine block cut from my previously made all cardboard sacrum to the completed block. Thin card templates of the sacral vertebea centra are glued to the block; these will help define the spool shapes of the fused vertebrae that make up the sacrum. Short tubes made from wound strips of paper extend the opening for the femoral dowel, acting as a guide for preventing the papier mache ( both pulp and strip) from filling these holes.

[Thagomizer]

More work on the toes and feet; mostly the hinges to go between the toes and the metatarsals. The hinge mechanisms are the same as those used for the toes except I've left out the spacer piece between the paired outer hinge plates; there's not going tho be a lot of space in the metatarsals for a very long hinge unit. Cutting them short meant that the spacer wasn't going to be worth adding (although I'd already gone ahead and made them...oh well.)

I thought briefly that I might build the metatarsals up from strip papier mache over a plasticine core (built up over thin card templates). Once dried, the papier mache would be cut open, the plasticine/card cores scooped out, and the resulting hollow shells assembled over a stronger,thicker card internal structure into which the hinges would be slotted. Nope. Didn’t happen. This is an instance where I'm showing you a wrong turn I made. Let this be a warning to you all! By the time I got the first few plasticine metatarsals done I realized they were going to be too thick even before the papier mache build-up. So I’m (probably) going to build directly on the thicker card structures I already have made up. Even still I will have to be careful that these don’t become too thick too.

[Thagomizer]

Big photo-dump; more work on the sacrum and pelvis. Some reality checks to compare what I'm doing to what I'm aiming for show me where I have to correct some shapes. The neural spines of sacral verts 4 and 5 are made a bit taller so that there isn't a big step up in height to the first tail vertebra neural spine. The front view using the Sue monograph shows I'm closer to target with the shapes than the view comparing my progress with the description of the type specimen from (I think) Osborn's 1912(?) look at skeletal adaptations inT.rex and other carnivorous dinosaurs.

There is a fair amount of variation in T.rex specimens; this is most evident in the skulls. But there is variation in the rest of the skeleton too. Some paleontologists suspect that North American Tyrannosaurus contains more than the single currently recognized species "rex" and that some of this variation is due to the presence of more than one species in the current mix of specimens. Sexual dimorphism (male or female?), stage of growth(juvenile or adult?), individual variation (Ralph or George?), geographical (Alberta or South Dakota or Montana?)and temporal (67 million years old or 65 million years old?)variation are probably all involved in producing the range of variation exhibited in the specimens found thus far. A nice bone bed of a T.rex pack (assuming they were social enough to have even formed packs) that died simultaneously would be very helpful in sorting a lot of this out. While such a find has been made for the slightly older and smaller Albertosaurus sarcophagus, T.rex finds have been, for the most part, isolated individuals.

Shapes are built up using pulped facial tissue mixed with diluted glue. The pubis (the vaguely putter-shaped bone on the lower front quadrant of the pelvic girdle when viwed from the side) is starting to take shape in corrugated cardboard.

[eveo]

This man is the next Leonardo!

[ROOSTERCAT]

BEAUTIFUL!!!!.

yOU ARE A GENIUS!! CONGRATULATIONS!!!

REGARDS.

-GALILEO

[Oritey]

keep going! we all support you!

[joel3d]

I just registered to support you.

[Thagomizer]

Thanks Joel!

Neat stuff on your site!

[SavageGoldfish]

Look! Someone else who uses cardboard and toothpicks to make stuff! XD It's great to see someone else out there making stuff out of paper mache, especially something to this scale of awesomeness, detail, and accuracy. It is definitely an underappreciated medium. You have certainly given me some inspiration and ideas for how to improve my own work with paper mache (I have a friend who is a film student/aspiring independant filmmaker, and whenever he comes to me with things he needs made for film projects, my answer is "Paper mache!!" because we're both dirt poor and nothing's cheaper.)

This is amazing. Your patience and dedication to this project is incredibile. Can't wait to see more!

[Thagomizer]

Lots of ground to cover this time; correcting the shape of the ilia, hip, knee and ankle joints, assembling the femora, refining the shape the of the tibiae, priming, sanding and re-priming.

First up, the ilia. The bits in black are to be trimmed off. I suspect that there was a bit of distortion induced in the cardboard form when I packed it with plasticine to make the master. A snip here, a snip there and it's done. Just as a bit had to be trimmed, a bit also had to be added. Again, very easy to do.

The hip joint mechanism is wire pushed through holes in a piece of dowel. The dowel will be glued into the sacrum but allowed to rotate in the femur in a sleeve of rolled paper. A retaining ring (also of rolled paper) keeps the dowel from pulling out of the sleeve.

At the other end of the femur is the knee joint. This is made using two bits of wire inserted through slots in the condyles. (Yikes, those slots sure look crude photographed way up close like that! With any luck they won't be that noticeable once the bone is painted dark brown and the knee is flexed. I hope.) The wire is anchored at either end in dowel pieces, which are secured with glue and pulp to their respective bone surfaces. Having two pieces side by side helps to minimize the chances of the joint moving in anything other than a parasagittal (fore and aft) plane. Similarly the ankle joint uses three side by side wires, anchored in dowel, passing through slots cut into the distal ends of the parts making up the tibiae, one pushed into each metatarsal. Having the dowel pieces a short distance away from the ends of the bone means the axis of rotation of the joint at the bending of the wire is inside the bone (as it would with a hinge joint) rather than between the bones. I know that wire will eventually wear out and break from fatigue, but so be it.

Pulp is used to improve the shape of the proximal tibiae; casting in a hard mold had dictated the simplification of this area to avoid undercuts that would have trapped the papier mache part in the plaster.

Once the joints are fixed in one of the half-femora (demi-femur or semi-femur?) the other half is glued and clamped. This is followed by sanding of the seams, priming, re-sanding and re-priming. The primer I'm using is a coloured acrylic gesso. The gesso is rather thick and tends to leave brushmarks; dabbing it on with a sponge solves this and also results in a nice "grainy" texture which looks more bone-like than the brush marks did! Careful dragging of the sponge along the surface results in a grain pattern suggestive of the direction of bone growth.

The ankle ends of the tibia are wired and reinforced. I suspect that this joint will be bent quite a bit; the triple wire will ( I hope) prove to be up to the task.

When next we meet (meat?) I should have the legs and feet finished. That is my intent anyway. We'll see what actually transpires...

[mvarelajones]

wow, finish the project! its looks awesome

[felixdasilva]

excelente proyecto

[SavageGoldfish]

About how sturdy are the hollow parts of those bones, or will you end up filling them in with something to make them more solid?

[Thagomizer]

Hi Jiangzu;

The hollow parts are actually pretty strong. I'm not going to be adding any filler. I've used wooden dowels for anchors and bending points because the papier mache wouldn't be strong enough on its own to withstand the repeated stress of reposing the limb joints. Also the papier mache does re-soften a bit as I add new, wet material to refine shapes, add the anchors or fill in the seams from joining the half parts. Once it dries again it's pretty sturdy. The completed skeleton is going to be mounted on a rod or dowel inserted into a socket in the pubic boot; the legs and feet will not be called upon to support the model's full weight. If it weren't built with reposing the limbs it would be strong enough to support its own wight, though I would probablably used a stiff wire armature for extra strength. I bipedal figure balancing a long, horizontal spinal column (particularly if it is a dynamic pose) is going to have more stress at the ankles and hips than a quadrupedal one in a more static pose.

The strength of a given part is going to depend on things like its diameter, what kind of paper and how many layers are used to build it up the form you're making. Adding cardboard to strategic parts while building a larger form might help to stiffen it too.

[GojulasPrime23]

This project is insane. Thagomizer, you're doing a great job of documenting your process for us- it looks amazing so far.
What book(s) are you using for reference?