Whilst it is usually the painstaking task of animating that makes stop motion projects take so long to create, in this case most of our time was spent constructing the dinosaur models. To get a rough idea, it took about 4 months to design and build the models, compared to about 1 month of shooting. This is partly due to the complexity of the models required, and partly because we were delving into some new model making techniques, which took quite a bit of experimentation. The animating was completed rather quickly because there was only around 1 minute of screen time required.
Our characters have generally been quite cartoony in the past, so it was a challenge to aim for something relatively realistic. The brief was to look similar to Ray Harryhausen's stop motion T-Rex and Triceratops from the 1966 film One Million Years BC, both in appearance and movement, as they had to fit in with the 1960's setting of Danger 5.
Initially, we drew designs and sculpted models out of clay to get the shape figured out. However, the difficult part was to create a fully functional animatable puppet. We had bought some ball-and-socket human shaped armatures for a previous project that we could modify into the shapes we wanted. We used sections of this for the arms and the legs, the parts that required the most movement, and used wood and aluminium wire to construct the rest.
For the T-Rex, we decided to base the model on a toy we found, and even use some parts of it. This proved handy later on when we needed to make a replica body to explode, when shot by a tank.
For the Triceratops, everything needed to be created from scratch. We sculpted individual sections, like the torso, head, and each limb out of plasticine. All the details and skin texture was sculpted into these parts. We made various textured rollers out of Sculpey oven-bake hardening clay, that could be rolled along the plasticine to give a scaly dinosaur skin texture. Then we created plaster moulds of these plasticine parts. In the moulds, we painted a layer of latex, which eventually formed the outer skin of the dinosaur. Then we placed the armature inside the mould, elevated in the appropriate position.
Next came the fun part. This project was the first time we'd used 2 part polyurethane expanding foam. This stuff is crazy! You mix together a small portion of parts A and B, and they react, expanding about 20 times the original volume in less than a minute. We bought a hard and soft foam formula, each required for different sections of the models. We poured this mixture over the top of the armature, into the plaster moulds, and closed them up. The foam then expanded to fill the mould.
When we opened the 2 halves of the plaster mould up again, we had the final shape of that section, with the armature on the inside, covered in expanding foam to fill out the bulk of the model, without making it too heavy, then covered in a latex skin. Each of these body parts needed to be joined together at the armature, so we left the ball or socket joint exposed so we could join them together. Then we covered the seams by painting latex into the gaps.
Finally, we gave the latex skin a paint job, using special latex paints that stick to the latex and stretch when it moves without cracking. We also added a few final details like eyes, horns, swastika drapes and machine guns to complete the model. The eyes were purchased from a doll maker, the horns were made from 'Knead It', a 2 part hardening material, the swastikas were ironed onto material and attached to the model with string, and the machine guns were toys that we modified a bit to suit the situation.
The T-Rex was created in much the same way, except we had the toy model to mould the original shape from. One of the challenges for the T-Rex was that it required a highly moveable jaw, which was constantly snapping at people. We made a hinge mechanism inside the head that was controlled by a external handle, sticking out the back of its neck. This handle could be rotated to control the opening and closing of the mouth in very small increments, ideal for animating. It just meant that we either had to try to hide this handle in shot, or remove it in post frame by frame.
We also created the neck and head of a long necked dinosaur. It did not need to be anything specific, but we decided to base it on a brachiosaurus. The body didn't need to be seen and it didn't require much movement, so the armature was pretty simple; just a piece of aluminium wire bent into shape. We did the same techniques, using plaster moulds, expanding foam and latex, but only required the one mould, so this model only took one week to make. Despite being a relatively simple model compared to the others, it came up great on screen and its limited movement made it really easy to concentrate on animating just a few aspects really well.
Much of the 4 months making these models was spent waiting for plaster or latex to dry. We tried speeding things up with fan heaters, which may have helped a bit, but didn't really help the power bill. It was frustrating at times but if we were working on multiple things at once it didn't matter too much. We learned a lot from this project and will definitely be using expanding foam and latex more in the future.