Yes, we finally turned the digital model of Australovenator's arm into a solid 3D printed reality!


So how did we do this?, Turns out there are a number of ways to "print out" a digital model. You can carve it out of  solid block of material using a computer-numeric-controlled (CNC) "chisel" (basically a spinning router bit mounted on a robotic arm). Or you can print it out in many many thin layers, one upon the other, until a three dimensional object is built up using a special 3D printer.

We chose the layer-by-layer method because we could get a very high level of finish in full color straight from the printer! 3D printing is often called Rapid Prototyping. It's expensive because it's slow to print each copy and requires expensive equipment to do the job. But it's still faster than old-fashioned "analog" sculpting methods and you get an exact copy of the model in every way, even scaled up or down in size. So industry often use 3D prints to "prototype" a product, i.e. to produce a test copy. Such copies are for research use and original prints are rarely seen outside of the development lab. That is of course unless only a single copy is ever needed, making the printout a sort of original artwork. Movie studios do this kind of thing to make props, for example.

We looked into several methods for printing our model before making a decision. The CNC carving method is OK for big jobs like large dinosaur bones but can't easily produce a high level of detail or very small objects like scaled-down miniatures. So we looked into thin layer printing. The cheapest method deposits a type of resin plastic in layers to create a hollow structure with a minimum external wall thickness of about 1 mm. You can print bones with a reinforcing 3D mesh inside,  a bit like real bone (as shown the picture below). The compromise is that printouts have a "layered" texture (see the closeup photo below). This type of print needs to be resurfaced and colored by hand to match bone texture,  i.e. fine grained on the shafts and polished on the joints. That's a lot of extra work!

The other layer-type technology we looked at was a full-color 3D print method from Z Corp. This method deposits a fine powder to give fully-finished and colored models straight from the printer. For this method, fine sheets of powder are built up like thousands of sheets of super-thin paper. A print head deposits glue and color to each layer one-by-one in just those areas that are to remain solid and part of the model. At the end of the process you have a huge block of white powder with a perfect model built-up in the middle of it. All you do is dust of the loose powder and you have a full color 3D model printed at 600 dpi (dots per inch) in 24-bit color. Amazing!

We were very lucky to find someone with the skills and equipment to help make our 3D printing a reality. David Cuthbert,  who owns and operates Zmodel was our man. David knows this technology backwards and he put a enormous effort into helping us achieve outstanding results. Because we wanted to create a full restoration to fresh bone (i.e. not a fossil-finish but bones that look like they are new and perfect) David helped by sourcing color maps for the models with the advice of Dr Scott Hocknull at Queensland Museum. Together they found and photographed representative "fresh" bones. These color images were "mapped" onto our model to give it an accurate lifelike look.

The Z Corp color printing method has some compromises however; it's slow to print and can only print relatively small objects. Printing a full-size arm was pushing the limit for size and almost every bone needed to be printed separately. The humerus (upper arm bone) is so large it had to be printed in two parts that were joined after printing. David was able to join all the separate printed bones with stainless steel and carbon fiber rods and mount them onto an acrylic stand. He also had a laser engraver so we could label the acrylic stands properly. We made extra copies of the full size hand and the 1:4 scale hand and arm so, if you're interested, you can own one! There's such a lot of work involved that we won't be making many, so put an order in soon if you want one (see the Art page of our online shop for details).