The visitors of Prague’s Zoo can enjoy an unusual sight: a life-size replica of a Triceratops skull. We used photogrammetry to create a 1:1 clone of an actual dinosaur skull and 3D printed it on our Original Prusa XL 3D printers. The final 226×153 cm sculpture is one of the largest things we have ever printed and weighs over 66 kilograms (145 pounds) without the stand. Let’s take a look at how we made it!
How large objects can be 3D printed?
If you ever pay a visit to Prague, Czech Republic, you can start your trip by delving much deeper into history than what the beautiful streets of the Old Town could possibly offer. Almost right next to Prague’s airport, there’s the POP Airport Shopping Center which hides a unique secret among its many apparel and cosmetics stores: a dinosaur museum called Dinosauria.
With actual 154 million-year-old fossils and many lifesize (and lifelike) models, the exhibition has something for every Jurassic Park fan out there. We got curious, too, of course, and a friendly chat with the staff of the museum quickly brought up two questions. First, it was “Can you scan a dinosaur skull and turn it into a 3D model?” and another question quickly followed: “So, can you perhaps print a life-size replica of the skull on your 3D printers?” to which our colleague immediately replied: “You bet jur-ass-i-can.”
Well, he didn’t phrase it like that, but we like to pretend he did. Either way, it resulted in a friendly challenge: let’s try to scan an actual Triceratops skull and create a 3D-printed replica.
Meet Trik the Triceratops
Trik is the dinosaur we scanned in the museum. Its skeleton was found in the Hell Creek Formation, Montana. The skeleton is 66 million years old and it was found in relatively well-preserved condition. Trik’s skeleton shows that he was extremely large, approximately 30% larger than is usual for Triceratops horridus. This is best demonstrated by his femur, which measures 30 cm more than in other individuals of this species – 132 cm, or approximately the height of a nine-year-old child. Trik could have measured up to 9 metres long and weighed about 12 tonnes, as much as three Indian elephants combined. The dents and injuries visible on his skeleton suggest that he survived many attacks during his lifetime – the large hole in the bony frill was likely caused by a T-Rex.
Triceratops, meaning “three-horned face,” was a herbivorous dinosaur that roamed the Earth during the late Cretaceous period, approximately 68 to 66 million years ago. This iconic dinosaur is known for its distinctive appearance, featuring a large bony frill at the back of its skull and three facial horns. The two long horns above its eyes and a shorter one on its nose made Triceratops one of the most recognizable and well-defended dinosaurs of its time.
One interesting fact about Triceratops is its sheer size, with some individuals reaching lengths of up to 30 feet and weighing over 10 tons. These powerful herbivores were capable of charging at potential threats or rivals, using their horns for defense and dominance displays. Fossils of Triceratops have been found in North America, particularly in regions like Montana, South Dakota, and Wyoming, providing valuable insights into the late Cretaceous ecosystems and the diverse range of dinosaurs that inhabited them.
Four hundred photos
There are several ways to create a digital replica of a real-life object, but only two were suitable for this task. A portable 3D scanner or photogrammetry. We chose the latter because of how accessible it is. If you own a DSLR camera and a moderately powerful PC, you can do this too.
We used a Fujifilm X-H1 to take nearly 400 digital photos of the entire Triceratops skeleton. These were then reduced to 250 best photos which we finally fed into the popular Reality Capture software. This software package can analyze hundreds of photos and turn them into detailed 3D objects. It comes at a price, though – we had to employ one beefy GeForce RTX 3080 GPU to process the photos in a reasonable amount of time. In our case, the result was a model featuring 5,219,328 triangles which was perfect because we needed as much detail as possible. And a little fun fact: despite we focused on the skull, the photos were enough to reconstruct the body quite well, too. But we were mainly interested in the skull, so we ended up cutting the rest of the model.
By the way, if you want to check out the skull, feel free to do so! The model is available at Printables.com!
Cut my skull into pieces
The massive skull had to be cut into smaller blocks that could be printed on the Original Prusa XL. Technically, we could make them even smaller, but it would mean that there would be way too many cuts. Even with the massive XL printer, we ended up splitting the model into 34 huge parts.
By the way, the recent PrusaSlicer release (2.6.1) features a completely reworked and vastly improved system for cutting objects. Apart from a simple cut via a plane, the tool now also supports advanced features, such as the possibility to add and configure various joints which makes assembling objects much easier.
In the end, it took nearly two liters of superglue to connect everything together. The resulting model measures 226×153 centimeters (7.4’’ by 5’’) and weighs 29 kilograms. However, there was still something left to do.
Survive under open sky
We knew that the skull would be displayed in Prague Zoo (one of the top zoos in the world) and it had to be protected against the weather – from scorching hot summers to freezing cold winters, rain and snow. And, of course, we had to cover up the seams between individual printed segments. First, we applied three kilograms of laminate to seal the sculpture.
Once the model was dry, we painted it using two liters of paint and the seams were masked with putty. Then it was time for some additional paint jobs to make the skull look more weathered and realistic. Finally, the model was covered in three liters of UV-protective clear coating.
From the start, we planned to put the skull on display. For this reason, we mounted a special custom-made metal frame into the skull that brought the total weight to 66 kilograms (145 pounds). Four people were required to load the print into a van.
The skull arrives
It was a job for four people to install the skull onto a massive steel support structure that was installed in the zoo in advance.
With its thick UV-protective clear coating, the skull should be able to withstand pretty much the all-year weather with no problems. So, if you ever pay a visit to Prague Zoo, you can check out one of the largest 3D prints we have ever produced.
And by the way, the model was cut into pieces by a very basic PrusaSlicer tool – its capabilities were massively expanded in the recent 2.6.1 release. However, there are many more changes, so feel free to check out our blog article that covers everything new and important.
If you want to print the skull yourselves, simply visit Printables.com and download it for free!