It has been 13 years since James Cameron made history for Avatar: The Way of Water was revealed, readying audiences for another journey to Pandora. They're also ready for the groundbreaking visuals that James Cameron is sure to supply just as he does every film.
Each one of Cameron's films have utilized or even perfected a new piece of visual effects technology and set the standard for films afterwards. But Cameron is just a part of the visual effects landscape in films and the technology for creating stunning sequences in movies has been crashing through barriers since the inception of film itself.
Rotoscoping
The rotoscoping technique was invented by Max Fleischer as a way to animate in a more realistic way. The technique involved tracing every frame of a live action film. This visual effect created an animation that moved in a very realistic way.
It did prove to be very labor-intensive as animators had to trace and retrace every movement of an actor's scene. Koko the Clown is one of the first and most famous examples of the technique, created in 1915. However, it still saw much use even as CGI came to prominence. The first three Star Wars films colored their lightsabers using rotoscope to trace over the wooden swords used by actors during post-production.
Double Exposure
The next step in putting two different pictures together was double exposure. In the days of black and white film, this was accomplished by filming the same scene twice, once with certain items covered in black velvet and again with the velvet removed.
This early form of green screen was put to great use in 1933's The Invisible Man and stunned audiences by overlaying the lead in black velvet except for certain items of clothing. He then performed his routine in front of a blacked-out set. That scene was then overlaid over a visible set and the Invisible Man was born.
Stop-Motion Animation
This very well known animation process is as old as the film industry itself. In the late 1800s, the zoetrope was a form of primitive stop-motion animation. Viewers would look into the device and watch the pictures spin around, each slightly different from the one before to create a moving effect.
As film technology improved, so too did the art of stop-motion. Animators increasingly used the time-consuming technique in their films the realness of the animated characters improved. Ray Harryhausen was a pioneer of the technique, patiently moving and rearranging his skeleton warrior models every frame for Jason and the Argonauts creating an effect where the human characters appeared to be fighting the animated monsters.
Sodium Vapor Process
Another name for the Sodium Vapor Process is "yellowscreen," which should go a ways to help to explain what kind of process this film technique is. It was an early form of greenscreen technology and was used extensively by the Walt Disney Company, particularly in Mary Poppins, for which they won the Academy Award for Visual Effects.
The technology involved filming an actor in front of a white screen that was lit with Sodium Vapor lights. These lights (which are often used in street lamps) have a narrow color spectrum. A special filming device was then used to separate the actor from the background leaving two photos, one of the actor and a perfect cutout of their silhouette over a white background. This made it incredibly easy for animators to then add drawings that fit perfectly with the actors movements.
Go Motion
Filmmakers struggled for years trying to perfect the art of stop-motion and animate it in a way that heightened realism. Every stop motion animation on film has a similar jerky quality because unlike in normal filming, the filmed model is perfectly sharp in every frame. This look has a charm of its own but directors and animators were striving for something that would mesh better with live action.
EnterIndiana Jones. Practical tricks like bumping puppets, rocking the set tables, and applying petroleum jelly to the camera lens were all techniques that created a realistic motion blur line to stop motion animatronics and models.
3D CGI
Computers completely changed the world landscape and the filming industry was no different. The new tool essentially gave animators infinite tools to design images and create effects in a real three-dimensional space in a way that could never be done on paper.
The first uses of the technology were for static creations that still amazed audiences worldwide. Futureworld, the sequel to original Computer generated image special effects appeared on screen and VFX artists got their first look at the possibilities' computer graphing could do for animation and film.
3D Computer animation
Generating computer images was one thing, but integrating them into film as real animations was a whole other step. In some ways, 3D animation was a successor to stop-motion rather than 2D animation as animators would create a 3D model and then animate every movement of their creation. The computer gave artists the ability to have control of every movement.
The characters in these 3D animations were created by modeling "skeletons" and then overlaying the desired skins, texture, or clothes over the model. Animation technology allowed for designers to then move the creation any way they wished. Toy Story, the door was wide open for the art form to take over the VFX industry.
Chroma Key
Chroma key is often better understood as greenscreen or bluescreen, which is when the actor is placed in front of one of the colored screens so that images, usually computer generated, can be added in post-production. The chroma key techniques audiences see today are extensions of the primitive black matte compositing used in the early-20th century.
The technique has received constant refinement and improvement across the decades and continues to be a staple of VFX studios. Lighting, camera exposure and depth of field are all variables that filmmakers have had to contend with in order to disguise the fact that actors are not in the environment shown on screen. To this day, audiences can spot hiccups in the effects in blockbusters as big as Avengers.
Bullet Time
The bullet time effect is often associated with one specific film, The Matrix, and this is where the term comes from but that movie only popularized and elevated a technique that has been around since the late-19th century. Bullet time essentially describes detaching the speed and movement of the camera (and therefore viewer) from the subject.
The effect of this bullet time can not be accomplished with normal slow motion or camera movements because the speeds required to capture something like a speeding bullet would be impossible. Instead, filmmakers like the Wachowskis, set up dozens of cameras in an arc around the subject. Each camera takes a picture in rapid succession and then those photos are stitched together to create a rapidly sweeping camera shot.
Motion Capture
Motion capture, or Mo-Cap, is the most recent application of computer generated VFX technology. It involves using reflective markers on the subject who is then asked to move and act naturally. Multiple cameras then capture the moving dots and transfer the resulting animation to a computer. This results in a basic, but natural, frame of movement that an artist can then animate over.
Pirates of the Caribbean, and Avatar all used the Mo-Cap technology to create completely computer generated characters such as Gollum and Davey Jones who fit in as well as any live-action character. Avatar went a step further, developing facial recognition technology that allowed the imperceptible face movements of actors to be translated to a CGI character.
