Virtual camera
From Wikipedia, the free encyclopedia
A virtual camera is a motion camera which is not real or a set of still cameras which are designed to behave as a motion camera, or is taking images of objects which are not real.
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[edit] Gaming
In computer games; a virtual camera refers to a viewpoint that cannot be seen. For example, an external camera in a 3rd person perspective. In early games this had to be represented by something so that the view that the person saw would be recognized by the Games' graphics engines. For example, in the Nintendo 64 game Super Mario 64, there was a small Lakitu character used as a "marker" for where the camera had to be (at one point in the game, looking into a large mirror would reveal Lakitu floating where the camera was).
Later, invisible-nonsolids were developed. (basically things which can be used, but not seen and don't have any effect physically on the world in which they work). An example is within Jedi Academy by lucasarts.
[edit] Film
[edit] Computer Animated Movies
In computer animated movies, the effect of a virtual camera is much that of a physical camera, it allows viewpoints to be used, without affecting the materials contained in the virtual world. The invisible nature of the cameras also avoids the need to keep removing them from shots in which they shouldn't be seen, but end up within the shot.
[edit] Special Effects
There are two main examples of this. Both of which are contained within the Wachowski Brothers' The Matrix Trilogy. The main reason for its use in both of these circumstances was that what was envisioned by the directors could not be done using conventional cameras.
[edit] Bullet Time
This involved a movement that moved full circle around a subject (in the case of The Matrix, a person). The problem with a conventional camera was that the rigs for the camera would be showing, in addition a virtual camera had more flexibility in terms of changing speeds.
The rig set up looked like this: 
Behind the black holes are conventional still cameras, except at the end of each dotted line were motion picture cameras are placed. The green material is called greenscreen. This is manipulated using a method called keying, to identify the colour of an area eventually to be replaced.
The cameras all fire in sequence as the motion to be taken is made. When the images are sequenced together (often filled in between frames using computer generated graphic frames, a method called interpolation) it appears that a camera has moved around the object. All that remains then is for the green area and cameras to be removed, and for a virtual area to be sub-imposed underneath the image of the object; and this results in a completed timeslice sequence, also popularly known under the trademarked name bullet time.
[edit] Fist camera
Essentially the Wachowskis wanted a camera that would simply follow a fist into Smith's face in the final scene of The Matrix Revolutions. The two problems with a conventional camera were that
- a) there was no way of attaching the camera
- b) there was no way of hitting Hugo Weaving's face full pelt without fracturing his jaw.
So essentially, they created a computer generated fist, created a computer generated Hugo, and propelled the fist into the face in slow motion. They then attached the virtual camera to the arm, and added a background; which led to the finality of the fist camera.
[edit] References
- Filmmaking - The Making of the Matrix Trilogy - originally shown on ITV, 2003.
- 3D movie making - XSI mod tool and 3D Studio MAX user manuals.
