Orc Skull With Moving Jaw
During my last semester of uni in 2021 I had the opportunity to showcase some work in my university’s art gallery. We were to make and show a capstone project for the event, along with the option to display some portfolio pieces with it.
My portfolio pieces were two animations of environments I had created, which can be found here and here. My capstone project was a mechanical orc skull.
Skull puppetry demonstration: https://www.youtube.com/watch?v=EX39WC2yfyo
Initially we weren’t given much direction or many limitations on what to do with our capstone projects, so I brainstormed a large amount of ideas on what I could make, in case one or multiple ideas weren’t eligible. But I knew that I really wanted to make something with mechanical puppetry, as I wanted to improve my engineering skills in mechanics. I also wanted to make something organic, another strong area of mine I love working in.
Some of the more refined ideas that came to me were to a make “ghoulified” head, with skin peeling off to show bone. I decided not to go in this direction because, firstly, I knew that children could be at the event and didn’t feel like being the blame of their nightmares. Secondly, at this point I hadn’t had any experience with latex, nor silicones outside the use for molds. Although I wanted to learn, I didn’t want to take the risk during the short time frame (~6 weeks) of learning a near entirely new skill.
So, I decided to make a skull. I still got to work with organic features and puppetry, but could make all the pieces solid. I also wanted to take some creative liberties with the skull, so instead of making a human skull, I chose to make an orcish skull. This was primarily inspired by the Lord of the Rings films, with influences from other reference images found online. Differing from a human skull, this one was wider, had lumps across the scalp, well-defined (and double) cheekbones, and fangs to finish it off. It also has an earring that hangs from its left side.
Design
After gathering some reference images, I started sketching rough shapes. Since I suck at sketching (a skill I need to improve), I didn’t stay too long in this stage and went onto experimenting digitally. Initially I sculpted a human skull (every 3D modelling aspect was done in Blender) based on a reference image, with the intention of deforming it to see what I liked. After stretching it sideways and vertically, I preferred it horizontally stretched, thus chose that. The eyes were shaped to give it an angry expression, and the lumps on the head were an experimentation with creating a different visual aspect to a human skull. After double checking it wasn’t a copy of Darth Maul’s head spikes, I was pleased with it. I didn’t add too much detail to the skull digitally, as the details would be created later on with physical sculpting.
To determine where to place the cracks on the skull, I printed off a side, front and rear view of the skull, and drew where, according to multiple human anatomical references, the cracks were most likely to go.
Construction
Both the skull and mechanics were printed from PLA+ on a CR10s. The skull was printed in two halves, then glued and plastic welded together. The fracture on the skull was carved into with a soldering iron and cleaned up with a file. The entire thing was also sanded with a palm sander, to give some texture for the sculpting material to grab on to.
Before finishing up the sculpting around the mouth area, I created the fangs. The original form of the fangs were sculpted from Monster Clay, formed around some wire for stability. Once sculpted into shape, I stroked the clay with a rough wire scrubbing pad to add texture. A mold wall was printed out and stuck to the foam board the clay fangs were attached to. Rebound 25 was the silicone of choice to mold the fangs with, which were then casted in Smooth Cast 300. Once cured, they were lightly adhered to the skull/jaw with copious amounts of super glue, just enough to hold it in place whilst I added more Free Form Sculpt around them. I once again used sculpting tools to add texture around the base of the fangs.
One thing I had to be cautious with the fangs about was that when the skull closes, the fangs should not collide with each other. This could scrape the paint off and cause damage to the casts. When the skull was assembled I tested opening and closing the fangs, and where there were ones that collided, I hovered right next to them with a soldering iron to warm them up and bend them away from each other.
Another part I resin cast were the earrings. These dangle from the side and are intended to give “secondary motion”, an effect that gives more life to a puppet through animation of parts (such as hair, antennae, etc) created from the physics of moving the puppet. The rings were 3D printed, sanded, and casted from the same silicone and resin as the fangs. Before casting however, the molds were dusted with aluminium powder, as well as cinnamon, for a rusty metal look. Once casted they were roughly polished and split in one section to link them together. During designing the skull, it was intended to have one ring piercing the nose too, however I forgot to include the hole for it before printing, and forgot to drill one before sculpting, and when I tried to do so afterwards, the nose cracked. So after patching the nose, I had to leave the idea of a nose piercing behind.
Mechanics
My goal for the orc skull was to have the head able to rotate on two axis, controlled by a user and a joystick. This concept was first seen by me from a course on Stan Winston’s School of Character Arts, with tutor Richard Landon, where the technique is used for tentacles and tails. The same concept was further studied in this Hackaday article by Joshua Vasquez, and this one too by Brian Poor. This was applied to the skull, though with only one “vertebrae” to control it. Although the mechanics did work in the end, even after a lot of trial and error, I had to ditch it and just rely on the jaw mechanism. As it turned out, where the mechanism attached to the skull underneath was too small, and the skull too heavy, that it was difficult to control the skull without it flopping around. In spite of having to abandon one of the primary features, I still consider it a small victory because the mechanism works, and taking what I learnt about weight distribution, I can apply it to another project.
Unfortunately I do not have any photos of the original mechanism, but it uses a ball and socket joint to rotate freely, with holes through rounded planes on the top/bottom for wires to pass through.
A major goal during the build was to keep the design modular. From previous builds I had learnt how important it was to make sure parts could easily be taken apart and put back together, for the purpose of problem solving, painting, upgrading, etc. I used screws/nuts, Chicago screws, and friction fittings to achieve this goal.
After all this I feel it still didn’t have enough texture, and wanted to add some grit to it so it looked like it had just risen from the ground. It occurred to me the best way to mimic dirt, was to use real dirt. It’s not something I would consider for a prop that was to be handled by a client, but since I was the only one touching this, I thought it to be OK. The dirt came from a volcanic town, where the soil was reddish from the minerals. The dirt was firstly sterilized with hot water. Using watered down Mod Podge for adhesion I applied this all around the skull, which proved to be abundantly helpful in creating texture. After that, both skull and jaw were coated with a matt clear coat.
The mechanics were also designed in Blender, and printed off. They underwent numerous changes as problems arose, which meant either reprinting them or modifying them by hand. The jaw trigger, for example, was reprinted about four times in total, to try and get the maximum range of pull on the cable, opening the jaw as wide as possible. This was done by extending the cable’s clamp away from the pivot point, and also by allowing a greater range of motion overall. Initially a spring was intended to be used inside to retract the trigger to its original position, but it was extremely difficult to install, and wasn’t too effective. So although it looks unprofessional, a rubber band on the front was much easier to install and held much stronger elastic potential. Since the exhibition was hosted while there was a pandemic still in play, gallery volunteers continually cleaned spots where visitors would interact with work. To make this easier for the volunteers, I wrapped electrical tape around the trigger so there was less surface area for dirt/germs to get caught in. I originally planned to use silicone for this purpose, but the orange-tan colour in combination with the elongated shape of the trigger made me think guests would be uncomfortable grabbing and squeezing it…
As the puppetry relied on the use of cables, and because I wanted to keep it all modular, I needed a way to hold wires in position to test/use the mechanics, while still having the ability to remove them when needed. The immediate solution that came to me were cable clamps, although I learnt that not only is “cable clamps” a broad term, but on the rare occasion I found what I needed, they were $9AUD+ for each unit. As I needed 10+ units, it was going to be very costly. The solution? Simply pick up a pack of small screws/nuts and print the clamps! The clamps were designed to allow the nut to be glued in, with a hole all the way through vertically for the wire to pass through, and a hole past the nut where the screw could go through and push the wire against the cylinder. For about 10 of these, the cost was under $10, which is mostly attributed to the screw/nut sets. When it was time to finalise the mechanisms, the clamps were glued in place, and the wires clamp inside of them.
Painting
In the final few days before the deadline for the exhibition, I was able to start painting. The skull and jaw were first given a coat of tan spray paint. Then a couple of washes of black, raw sienna and crimson red were applied to get some varied “dirty” base colours. Brown oil paints were used for shading, including in the nose, around the teeth, eyes and cheekbones. A light layer of black oil paint was used for further, darker shading.
To create the details and texture on the skull and jaw, they were both covered in Smooth On’s Free Form Sculpt. Because of its solid physical properties, even before curing I found it difficult to mix together at first, so there are a few small patches here and there where it hasn’t cured properly, and is therefore soft. Later on I learnt to mix in some water when kneading it together to soften it and mix properly. The head and jaw were done in multiple parts, and while it was still uncured, I used sculpting tools to add in the cracks, some minor dents, and a chip brush dabbed all over to add some texture the paints would bring out.