Module 26 - 2
Virtual Reality Sets
Within the last decade computer-generated graphics have moved into a whole new arena: simulating complete settings. These are referred to as virtual reality sets.
The color of the background that can be used for keying is normally either green or blue. As shown below, the color can be electronically removed and another video source inserted (keyed in) to replace it.
In this case a model in a studio sitting in front of a blue background is placed in a computer-generated scene.
Although this is a fantasy scene, very realistic settings can now be computer generated and keyed in behind talent. (Note the computer-generated scene below.)
"Green screen" backgrounds have been common in movies for decades. (Green was typically used for special effect backgrounds in film, and blue in video.)
In the 2007, three-part, Sci-fi Network production, Tin Man, for example, the elaborate backgrounds were created in a computer and the actors simply acted in front of a solid green background.
On the left a model with a fan in front of her is made to look as if she is bouncing along on a jet-ski in the ocean. The large electric fan provides the "breeze."
A video recording of the ocean and surrounding scenery taken from the back of a speeding boat is keyed into the green area behind her.
This results in a realistic scene, and the model doesn't even have to get her hair wet!
If it stopped here, the "realism" would be confined to one point of view. But in the real world cameras move and perspectives change. Let's look at an example.
Note the woman standing against the blue background on the right. Now look in the two monitors at the top of the photo and notice that a complete setting has been inserted (keyed into) this live scene.
Although the woman may not be able to actually sit down in the chairs seen in the setting, she can convincing walk behind them and they will pass in front of her body as she moves.
However, she can sit down on the blue box shown behind her in this photo, which, if things are positioned correctly, can make it appear that she is sitting down on one of the virtual reality chairs.
The camera can pan, tilt, and zoom in on her, and the keyed-in setting will shift appropriately.
This enlargement of the TV monitor above the woman shows the complete effect in more detail as seen from the camera's position.
Why use virtual reality settings?
The little white dots on the male and female subjects in this photo are used in motion tracking (also referred to as motion capture or mocap, and performance capture).
A video camera tracks the movement of these subjects (actually, the dots) and transfers the data to animated figures in a computer.
The action is normally transferred to an elemental wire frame version of the animated drawings.
Once the action is established, the computer can be used to "flesh out" the drawings to resemble any desired figure.
This process not only greatly simplifies the process of animating figures, but since the white dots represent numerous points of movement, it results in more realistic action.
Motion tracking took a major step forward with the 2007, 3-D film Beowulf, based on the English epic poem, circa 700 A.D.
In this case both the actors and the backgrounds originated in digital electronics.
Real actors such as Angelina Jolie (here) and Anthony Hopkins were used, but they were digitized by motion tracking, altered, and then put into virtual reality sets.
Added to this was a bevy of computer created creatures and monsters that (fortunately) are worse than anything we find in reality.
In late 2009, James Cameron's film, Avatar, was released. The film quickly became the most financially successful motion picture in history. .
The futuristic 3-D spectacle about love and war set on a distant moon, took motion tracking (performance capture) and animated realism to a new level.
Using this motion or performance capture technique, camera movements were also recorded while the "real" human actors went through their parts and animated their respective computer generated counterparts. Backgrounds, props and associated scenery moved in relation to the actors.
For subtle facial expressions a separate camera was focused on colored dots on the faces of "real" actors that went through all the motions of their associated avatars. This enabled computers to track changes in facial expressions and transfer the changes to their computer generated likenesses.
Avatar, which relied on computers and high-definition video cameras, was released in 2-D, 3-D and IMAX 3-D.
This link will take you to more information on 3-D film and TV.
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