The following list explains the different projection types that can be used with the camera. The most common types are the perspective and orthographic projections. In general the CAMERA_TYPE should be the first item in a camera statement. If none is specified, the perspective camera is the default.
Perspective projection
:
The perspective specifies
the default perspective camera which simulates the classic pinhole camera.
The (horizontal) viewing angle is either determined by the ratio between
the length of the direction vector and the length of the right vector or
by the optional keyword angle, which is the preferred way. The viewing
angle has to be larger than 0 degrees and smaller than 180 degrees. See
the figure in "Placing the Camera" for the geometry of the perspective
camera.