Category: issue 11 – Computer animation proudly presents

The art of animatronics, or how to build a believable dinosaur

Tyrannosaurus image by Eric Labayle from Pixabay

How do you create a full-sized dinosaur without a hint of computer graphics? The answer is through the amazing art of animatronics. Animatronics is a field of special effects that uses sculpture, mechanics, electronics and computer engineering to create life-size moving creatures for films and theme parks. They’re like puppets only much bigger, much smarter and much scarier. While today many film creatures are created using computer graphics in post-production, some filmmakers prefer to have their creatures ‘live’ on the set so the human actors have a real co-star to act along with. In a theme park, animatronics can put a weird creature, like a zombie pirate or a great white shark, right there and in your face. Famous movie animatronics stars include the shark in Jaws, the gigantic Spinosaurus in Jurassic Park III and the lovable alien in ET. How are these amazing effects created? Let’s get primeval with some state-of-the-art computer science.

On and off the drawing board

An animatronic creature starts out in life as a sketch on the drawing board. In some cases it’s a new creature-tastic idea thought up by the designer. In the case of dinosaurs, the sketches are created with the help of expert paleontologists. The sketches are then converted into a scale model, called a maquette. This scale model allows the designers to examine and correct their design plans before the big money is spent bringing the creature to full size ‘life’.

Growing up

Here’s where the model goes from the small to the large. The mini maquette is laser scanned, capturing all the detail of the model sculpture and feeding it into a computer aided design (CAD) software package. From this data whirring, computer-controlled blades automatically sculpt a full sized model using blocks of polyurethane foam. The blocks are assembled like a big 3D jigsaw, and sculptors add the extra fine detail. Now it’s big, it’s real and it’s ready for its screen test!

Pouring in the skin

If the full-sized version shows that star quality, it gets molded. Using the life-size model a set of moulds are made to allow the outside skin of the creature to be created. With the outside finished, now you have to think about the insides – namely, the skeleton, the mechanics of which depend on how the creature will be expected to move. Using a rough shape corresponding to the form of the core skeleton innards, the outer foam rubber skin can be poured in so that it only fills the negative space between the outside creature shape and in the inside skeleton. This reduces the weight of the skin and allows more believable, flexible movements.

More than just the bare bones

Skin done, now the technology really kicks in. The animatronics skeleton inside the creature is where all the smart stuff happens. It’s clever and custom made. It has to be – it’s the part that moves the outside skin to make it look believable. Attached around the main skeleton frame, which is often built with strong-but- light graphite and looks a lot like the real creature’s skeleton, we find the actuators. These are little clumps of clever computing that move the pieces around to make the creature look alive. Computer science abounds here, along with other state-of-the-art techniques. Mechanical and electronic engineering combined with computer-controlled motors are used to move small expressive bits like eyes, or to control the more heavy-duty hydraulic systems that move limbs. The systems may be pre-programmed for characteristic behaviours like blinking or swiping a claw. In essence the animatronics under the skin produce a gigantic remote controlled lifelike puppet for the director to play with.

Does my bum look big in this?

Putting the skin over the animatronics isn’t always easy. As each of the sections of foam rubber skin are added to the skeleton the construction team needs to check that the new bit of skin added doesn’t look too stretched, or too baggy with lots of unsightly flabby folds. One cunning way to help the image conscious creature is to use elastic bungee cords to connect areas of the skin to the frame. These act like tendons under the skin, stretching and bunching when it moves, and making the whole effect more relaxed and natural. Once the skin is on, it’s a quick paint job and the creature is ready for its close up. Action – grrrr -– shriek! Computer science takes centre stage.

Paul Curzon, Queen Mary University of London

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100,000 frames – quick draw: how computers help animators create

Ben Stephenson of the University of Calgary gives us a guide to the basics of animation.

Film projector with film strip on a coloured rainbow background, from Pixabay
Film projector and film strip image by Gerd Altmann from Pixabay

Animation isn’t a new field – artists have been creating animations for over a hundred years. While the technology used to create those animations has changed immensely during that time, modern computer generated imagery continues to employ some of the same techniques that were used to create the first animations.

The hard work of hand drawing

During the early days of animation, moving images were created by rapidly showing a sequence of still images. Each still image, referred to as a frame, was hand drawn by an artist. By making small changes in each new frame, characters were created that appeared to be walking, jumping and talking, or doing anything else that the artist could imagine.

In order for the animation to appear smooth, the frames need to be displayed quickly – typically at around 24 frames each second. This means that one minute of animation required artists to draw over 1400 frames. That means that the first feature-length animated film, a 70-minute Argentinean film called The Apostle, required over 100,000 frames to create.

Creating a 90-minute movie, the typical feature length for most animated films, took almost 130,000 hand drawn frames. Despite these daunting numbers, many feature length animated movies have been created using hand-drawn images.

Drawing with data

Today, many animations are created with the assistance of computers. Rather than simply drawing thousands of images of one character using a computer drawing program, artists can create one mathematical model to represent that character, from which all of his or her appearances in individual frames are generated. Artists manipulate the model, changing things like the position of the character’s limbs (so that the character can be made to walk, run or jump) and aspects of the character’s face (so that it can talk and express emotions). Furthermore, since the models only exist as data on a computer they aren’t confined by the physical realities that people are. As such, artists also have the flexibility to do physically impossible things such as shrinking, bending or stretching parts of a character. Remember Elastigirl, the stretchy mum in The Incredibles? All made of maths.

Once all of the mathematical models have been positioned correctly, the computer is used to generate an image of the models from a specific angle. Just like the hand-drawn frames of the past, this computer- generated image becomes one frame in the movie. Then the mathematical models representing the characters are modified slightly, and another frame is generated. This process is repeated to generate all of the frames for the movie.

The more things change

You might have noticed that, despite the use of computers, the process of generating and displaying the animation remains remarkably similar to the process used to create the first animations over 100 years ago. The animation still consists of a collection of still images. The illusion of smooth movement is still achieved by rapidly displaying a sequence of frames, where each frame in the sequence differs only slightly from the previous one.

The key difference is simply that now the images may be generated by a computer, saving artists from hand drawing over 100,000 copies of the same character. Hand-drawn animation is still alive in the films of Studio Ghibli and Disney’s recent The Princess and the Frog, but we wonder if the animators of hand-drawn features might be tempted to look over at their fellow artists who use computers and shake an envious fist. A cramped fist, too, probably.

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EPSRC supports this blog through research grant EP/W033615/1.