How Animatronics Works

By: Jeff Tyson

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Long before digital effects appeared, animatronics was making cinematic history. Who can forget the scare of the Great White coming out of the water in "Jaws"? Or the tender otherworldliness of "E.T."? Through the precision, ingenuity and dedication of their creators, animatronic creatures often seem as real to us as their flesh-and-blood counterparts.

What exactly is an animatronic device? Basically, an animatronic device is a mechanized puppet. It may be preprogrammed or remotely controlled. The device may only perform a limited range of movements or it may be incredibly versatile.

Photo courtesy Universal Studios
The Spinosaurus in action.  See more animatronics pictures.

In this article, we will focus on Spinosaurus, an animatronic dinosaur created for "Jurassic Park III" by Stan Winston Studio (SWS). You will learn how SWS worked with Universal Studios and the film's production team to develop the Spinosaurus design. We'll also discuss the amazing process that creates and controls a huge animatronic dinosaur like this one!

Special thanks to Stan Winston, John Rosengrant, Stiles White and the rest of the folks at Stan Winston Studio, and Brett Levisohn at Universal Studios for their assistance in creating this article. Look for the Spinosaurus in the movie "Jurassic Park III" from Universal.

Logo courtesy Universal Studios


Jurassic Machines

The "Jurassic Park" series is known for the realism of its creatures, both the animatronic and digital versions. When the original "Jurassic Park" came out in 1993, it set a new standard for the realistic portrayal of dinosaurs, creatures that have never been seen alive by man. "Jurassic Park II: The Lost World" continued to improve the vision, and "Jurassic Park III," the latest movie in the series, raised the bar once again.

Photo courtesy Stan Winston Studio, photographer Chuck Zlotnick
An animatronic Tyrannosaurus rex (T. rex) being built

Photo courtesy Universal Studios
The animatronic Spinosaurus in action

Most of the animatronic dinosaurs used in "Jurassic Park III" are new. For example, the Velociraptors were redesigned to more closely resemble what paleontologists think a Velociraptor looked like. The Tyrannosaurus rex was redone too, but is no longer the star of the franchise. That distinction now passes to Spinosaurus, a monster that dwarfs even the mighty T. rex. This is the largest animatronic creature SWS has ever built, even bigger than the T. rex that Winston's team built for the original "Jurassic Park"!

Check out these amazing Spinosaurus statistics:

  • It is 43.5 feet (13.3 m) long -- almost as long as a bus -- and weighs 24,000 pounds (10,886.2 kg/12 tons).
  • It is powered entirely by hydraulics, even down to the blinking of the eyes. This is because the creature was made to work above and below water.
  • There are 42 hydraulic cylinders and approximately 2,200 feet (671 m) of hydraulic hoses.
  • The creature moves on a track that is 140 feet (43 m) long and made from a pair of 12-inch (30.48 cm) steel I-beams.
  • All pivots use roller-bearing construction.
  • All large steel pieces were cut using waterjets.
  • The creature is completely remote-controlled.

How did SWS build this amazing device? In the next section, we'll look at the standard process used to develop animatronic devices. We will then look in detail at the various steps involved.



Dinosaur Evolution

The Spinosaurus is based on a real dinosaur that paleontologists have recently discovered. This basis in reality can be both good and bad for the design crew. The good side is that they have a solid foundation to start with. The bad side is that it provides a very specific set of criteria that must be matched.

Image source: Universal Studios
The Spinosaurus is the largest meat-eating dinosaur ever discovered.

Building the Spinosaurus, or any other animatronic figure, requires several major steps:

  1. Put it on paper.
  2. Build a maquette (miniature model).
  3. Build a full-size sculpture.
  4. Create a mold (from the sculpture) and cast the body.
  5. Build the animatronic components.
  6. Put it all together.
  7. Test it and work out any bugs.

A complicated animatronic figure could take up to two years from conception to completion. However, deadlines and budgets typically don't allow for a timeline like that. According to John Rosengrant, SWS effects supervisor for "Jurassic Park III," the Spinosaurus took less than a year to go from the drawing board to the finished product. Rosengrant supervised a crew of about 75 SWS designers, engineers and artists who worked on "Jurassic Park III" animatronics, and approximately 30 of them worked on developing the Spinosaurus.

On the next page, we will go through the first two steps of this process.



In the Beginning

The first two steps in creating an animatronic figure are the sketches and the miniature model.

Put it on Paper
The first thing that happens with any animatronic figure is that an artist creates preliminary sketches of the creature. The Spinosaurus sketches were developed by working closely with expert paleontologist Jack Horner and the crew working on "Jurassic Park III." The sketches are analyzed and changes are suggested. Eventually, the artist creates a detailed illustration of the creature. In the case of Spinosaurus, SWS went from preliminary sketch to final design in about three weeks.

Photo courtesy Stan Winston Studio, photographer Chuck Zlotnick
An artist sketches the Spinosaurus.

The paper sketches are vital. Everything else relies on the accuracy of these designs.

Build a Maquette
From the final paper design, a miniature scale model called a maquette is created. Fashioned out of clay, the first maquette SWS made of Spinosaurus was one-sixteenth scale. This initial maquette is used to verify that the paper design is accurate. If there are any problems, they are corrected and a new paper design is made.

Photo courtesy Stan Winston Studio, photographer Chuck Zlotnick
Jurassic Park III Director Joe Johnston and the one-fifth-scale maquette of the Spinosaurus

Next, a one-fifth-scale maquette is made. This sounds small, until you realize the sheer size of the Spinosaurus. The one-fifth-scale model was about 8 feet (2.4 m) long! The larger maquette allows the designers to add more surface detail. This maquette is then used to produce the full-size sculpture.


Big as Life

Once the sketches and models are done, the full-size building begins.

Build a Full-size Sculpture
For the animatronic dinosaurs in the original "Jurassic Park," SWS had to build the full-size sculpture by hand, a time-consuming and laborious process. Advances in computer-aided manufacturing (CAM) allow them to automate a significant part of this step.

The maquette is taken to Cyber F/X, where it is scanned by a 3-D digitizer. This is nothing like a normal computer scanner. There are a variety of methods used in 3-D digitizers, but the one that was used for Spinosaurus is called laser scanning.

Laser scanning takes precise measurements of the maquette by bouncing beams of laser light off its surface. As the laser scanner moves around the maquette, it sends over 15,000 beams per second. The reflected light from the beams is picked up by high-resolution cameras positioned on either side of the laser. These cameras create an image of the slice (cross section) of the object that the laser is scanning. A custom computer system collects the cross sections and combines them to create a perfect, seamless computer model of the maquette.

Photo courtesy Stan Winston Studio, photographer Chuck Zlotnick
Details are carved into the full-size sculpture.

Cyber F/X then used the computer model to mill the life-size model of the Spinosaurus from polyurethane foam. This very rigid foam is cut to the correct shape through a proprietary process called CNC-Sculpting®. This process, developed by Cyber F/X, takes the data from the full-scale computer model and divides the model into manageable chunks. The data for each chunk is then sent to the foam-sculpting machine, where a life-size section of the dinosaur is created by whittling away pieces of foam from a large, solid block using tiny spinning blades. Once all the sections are done, the SWS team assembles the pieces like a giant 3-D jigsaw puzzle. This creates a very basic full-sized model. A lot of work still needs to be done and it is handled by a team of sculptors at Stan Winston Studio. They hand-carve the foam to add all the incredible details that make it seem real.

Molding and Casting
A set of molds are made of the full-sized sculpture. The molds are made from an epoxy that is very durable and has strong bonding characteristics.

Photo courtesy Stan Winston Studio, photographer Chuck Zlotnick
Creating the mold

Once the components of the animatronic device are ready, much of the frame work is test fitted inside the molds before the foam rubber skin is cast. In conjunction with this step is the fabrication of the foam-running core, which is created by lining the inside of the mold with precise layers of clay to represent the skin thickness. When the clay lay-up is completed, the surface of the clay is fiberglassed to create the foam-running core. After the clay is cleaned out, the foam-running core is bolted into the mold and creates a negative space between the foam-running core and detailed surface of the mold. When filled with foam rubber, this negative space becomes the skin.

The purpose of this process is twofold:

  • It makes the skin movement seem more natural
  • It controls the skin's thickness and weight

Let's move on to the building of the animatronic components.


Creature Creation

Building the various components used in the animatronic device usually takes the longest time. Most of the creatures that are developed at Stan Winston Studio require parts that you're not going to find at your local hardware store. When is the last time you saw a left forearm for a Spinosaurus sitting on the shelf at Home Depot? This means that SWS has to build almost everything themselves. They do take advantage of any existing products when possible, usually by repurposing parts of a common device to fill some of their uncommon needs. This creative use of generally available items is probably the best way to learn how to do animatronics yourself, as demonstrated on this page.

Photo courtesy Stan Winston Studio, photographer Chuck Zlotnick
Working on the head of Tyrannosaurus rex

Basically, there are four main categories that the work splits into, with development happening simultaneously across the categories.

  • Mechanical - SWS engineers design and build the mechanical systems, which includes everything from basic gears to sophisticated hydraulics. An interesting fact about the animatronic Spinosaurus is that nearly all of the mechanical systems used in it are hydraulic.


  • Electronic - Another group develops the electronic control systems needed to operate the animatronic device. Typically starting from scratch and creating their own custom circuit boards, these engineers are essentially building giant remote-controlled toys. Almost all of the movement of the Spinosaurus will be manipulated by specialized remote-control systems known as telemetry devices. We discuss the specific telemetry devices used in the next section.

    Photo courtesy Stan Winston Studio, photographer Chuck Zlotnick
    All hydraulic systems are installed and checked.


  • Structural - All of the electronic and mechanical components need something to attach to and control, and the skin must have a frame to maintain its shape. This is done by building a plastic and steel frame. To increase the realism, and because it is the natural way to design it, the frame of the Spinosaurus, as well as most other creatures made by SWS, resembles the actual skeleton of the beast. This skeletal frame is largely comprised of graphite, a synthetic material known for its strength and lightness.


  • Surface - The "skin" of the Spinosaurus is made from foam rubber, which is a very light, spongy rubber that is made by mixing air with liquid latex rubber and then curing (hardening) it. While there are other compounds, such as silicone and urethane, that are stronger and last longer, foam rubber is used because it is much easier to work with. The solution is poured into each mold and allowed to cure. As mentioned earlier, parts of the frame are embedded with the foam rubber at certain points. To further strengthen the skin, a piece of fabric is cut to size and embedded in the foam rubber after it is poured into the mold. Once cured, each piece of skin is pulled from its mold.


Putting it Together

When all the components are done, it's time to build the Spinosaurus. The frame is put together and then the mechanical systems are put in place. As each component is added, it is checked to ensure that it moves properly and doesn't interfere with other components. Most of the electronic components are then connected to the mechanical systems they will control. The controls have been tested with the mechanical systems prior to final assembly, but the systems are checked again.

Photo courtesy Stan Winston Studio, photographer Chuck Zlotnick
The "skeleton" of the Spinosaurus

Parts of the skin that have embedded pieces of the frame in them are put in place when the frame is assembled. The other skin pieces are fastened in place on the frame once the mechanical and electronic components are installed. Assembling the skin is a very laborious process. As each piece is added, the team has to check to make sure there are no problems, such as:

  • Unwanted folds
  • Buckling
  • Stretching
  • Too tight

Whenever one of these problems occurs, the skin must be adapted or attached differently. Also, there are places where you do want the skin to fold or hang loose or travel in a certain way, and it must be adjusted to achieve that effect. One of the tricks that SWS uses to make the Spinosaurus and other dinosaurs seem more realistic is to attach bungee cords between areas of skin and the frame. During movement, these bungee cords simulate tendons under the skin, bunching and stretching.

Photo courtesy Stan Winston Studio, photographer Chuck Zlotnick
Painting the skin

The skin is mostly "painted" before it is attached to the frame. Stan Winston Studio does not use actual paint, though. Instead, a specially formulated mixture that is akin to rubber cement is used. Tints are added to the mixture to get the correct color. Rosengrant says that they use this mixture in place of traditional paint because it bonds more strongly with the foam rubber and stretches with it as the animatronic moves.

Once the animatronic device is complete, the team has to test it and work out any problems.


Making it Move

The people that control the animatronic figure are called puppeteers, because that is all that an animatronic device is -- a sophisticated puppet. These puppeteers are skilled actors in their own right and will spend some time with the animatronic figure learning its range of movements. Rosengrant calls this "finding the performance." The puppeteers are determining what movements make the animatronic figure look angry, surprised, hungry or any other emotions or moods that are called for in the script.

Photo courtesy Stan Winston Studio, photographer Chuck Zlotnick
The telemetry device for controlling the arms

Eight puppeteers operate the Spinosaurus:

  • Basic head/body - swivels head, opens and closes jaws, moves neck back and forth, makes body sway from side to side
  • Tongue slide levers - moves tongue up and down, side to side and in or out
  • Eye joystick control - eyes move, eyelids blink and eye ridge moves
  • Front arms - full range of motion; hands open and close
  • Cart/body - moves creature back and forth on track
  • Breathing potentiometer - inflated bladder inside chest cavity simulates breathing
  • Tail - full range of motion
  • Body raise slider - raises and lowers body

Rosengrant is the coordinator, and he makes sure that all of the other puppeteers are working in concert to create a realistic and believable motion. The telemetry devices used to control the Spinosaurus range from simple handheld units, reminiscent of a video-game joystick, to bizarre contraptions you wouldn't find anywhere else. For example, the puppeteer who controls the arms has a device that he straps onto his own arms. He then acts out the movement he wants the Spinosaurus to make, and the telemetry device translates his motion into a control signal that is sent to the circuit board controlling the mechanical components that comprise the arm system of the Spinosaurus.


Mouse over the arrows to rotate the dinosaur's head.
As you move the head, hold down your mouse button to open the mouth.



Monster Mash

Because the animatronic Spinosaurus is controlled by radio-frequency (RF) devices, certain precautions must be taken when it is in use. Any other device, such as a cell phone, that operates using RF technology must be turned off in the vicinity of the animatronic device. Otherwise, improper signals can interfere with the control signals. This could have disastrous effects when dealing with a 12-ton monster. Clean power is important for the same reason. The Spinosaurus has a dedicated uninterruptible power supply (UPS) so that a power surge or brownout would not cause it to go out of control.

Rosengrant calls the Spinosaurus a "hot rod" animatronic device. Everything on the Spinosaurus has more power than usual. The hydraulics have larger cylinders than normal and provide approximately 1,000 horsepower. The Spinosaurus is such a powerful machine that it can literally tear a car apart. When the tail is whipped from one side to the other, it reaches 2 Gs at the tip (1 G is the force of Earth's gravity).

Photo courtesy Universal Studios
The incredible realism of the animatronic Spinosaurus gave the actors ample reason to appear terrified.

On the set, the animatronic Spinosaurus was bolted onto a platform that moves on a track like a train does. An 18-foot (5.5-m) hydraulic cylinder was attached to the back of the Spinosaurus to move it forward very quickly. Moving the Spinosaurus to another location required a crane to lift it.

Since a lot of the action in "Jurassic Park III" involves water (mist, rain and lakes), the Spinosaurus had to be waterproof. Stan Winston Studio sealed everything tightly, providing enough protection that the machine could be completely submerged and still operate!

When watching any of the Jurassic Park movies, the blending of the animatronic and digital versions is extraordinary. Very few people can distinguish between them on the screen. However, Stan Winston says there is an easy way to tell if a dinosaur is digital or animatronic: If you can see the entire creature, legs and all, moving across the screen, then it is digital. The majority of other shots, particularly close-ups, probably use the animatronic version. Most animatronic figures, the Spinosaurus included, do not have legs. The ones that do are generally not capable of completely free movement.

Photo courtesy Universal Studios
Onscreen, the digital Spinosaurus from Industrial Light & Magic is hard to distinguish from its animatronic counterpart.

The dinosaurs of "Jurassic Park III" are incredible examples of the state of the art in animatronic technology. After seeing the Spinosaurus animatronic figure up close and actually touching it, I am amazed at how reality can be shaped so intricately by these masters of their craft.

To learn more about animatronics and related topics, check out the links on the next page.