Whilst it is probably good practice to setup cameras and lights in your worlds, in many VRML viewers it isn't required. Netscape's plugin will automatically move the camera so that all the objects in the scene are in view unless a camera node is used. It will also give some background lighting if no lights are defined in the scene. Cameras define where the viewer starts in the world, as well a certain other values such as in which direction they are looking, focal distance etc. Light nodes define what colour the lights are, where they are, how bright they are etc.

OrthographicCamera

An OrthographicCamera does not diminish objects with distance, whereas the PerscpectiveCamera does. The viewing volume for an OrthographicCamera is a box. The position parameter defines where it is initially placed, whilst the orientation parameter decides the direction in which the camera is "looking". The height parameter sets how "tall" the viewing volume is. The focalDistance sets the distance at which an object is in focus, although out of focus objects may be drawn as in-focus by many browsers.

Parameter	Default Value	Data Type
focalDistance	5	Float
height	2	Float
orientation	0 0 1 0	Rotation
position	0 0 1	Vector3D

Example: Setup a camera at (4,1,5).

OrthographicCamera {
	height 1.7
	position 4 1 5
}

PerspectiveCamera

Unlike the OrthographicCamera, this camera diminshes objects with distance. Whereas the OrthographicCamera has a box for it's viewing volume, a PerspectiveCamera has a pyramid as it's viewing volume, with the camera at the top peak of the pyramid, looking straight down. The heightAngle parameter defines the total vertical viewing angle of the camera. All other parameters are the shared with OrthographicCamera.

Parameter	Default Value	Data Type
focalDistance	5	Float
heightAngle	.785398	Float
orientation	0 0 1 0	Rotation
position	0 0 1	Vector3D

Example: Setup a PerspectiveCamera at (0,0,0), looking towards positive x.

PerspectiveCamera {
	position 0 0 0
	orientation 1 0 0 0
}

DirectionalLight

Use this node to create a light source that illuminates along a defineable 3D vector. The DirectionalLight is unlike the two other lights in that it isn't a point source (e.g. a bulb), but more like a flat light-emmiting surface. It could also be thought of as a point source an infinite distance away, similar to the sun at mid-day. The direction parameter selects the direction which the light shines in, NOT from. Like the other lights, you can set it's colour using the color parameter.

Parameter	Default Value	Data Type
color	1 1 1	Colour
direction	0 0 -1	Vector3D
intensity	1	Float
on	TRUE	Bool

Example: Create a yellow light coming from positive x.

DirectionalLight {
	color 1 1 0
	direction -1 0 0
}

PointLight

This creates a point light source at a definable point in space. The light shines in all directions (i.e. it is omnidirectional). The location parameter defines where the light is.

Parameter	Default Value	Data Type
color	1 1 1	Colour
intensity	1	Float
location	0 0 1	Vector3D
on	TRUE	Bool

Example: Create a dim cyan light source at (4,3,-3).

DirectionalLight {
	color 0 1 1
	intensity 0.3
	location 4 3 -3
}

SpotLight

This creates a light source as a definable point in space. Unlike the PointLight, a SpotLight provides a cone shaped illumination. The direction parameter defines the central axis of this cone, whilst the location parameter defines where the apex of the cone is. The dropOffRate defines how quickly the intensity of the light drops (the intensity decays in accordance with the inverse square law). The cutOffAngle parameter defines the angle of the cone.

Parameter	Default Value	Data Type
color	1 1 1	Colour
cutOffAngle	0.785398	Float
direction	0 0 -1	Vector3D
dropOffRate	0.0	Float
intensity	1	Float
location	0 0 1	Vector3D
on	TRUE	Bool

Exmaple: Create a red spotlight at (1,2,3) shining "down".

SpotLight {
	color 1 0 0
	direction 0 -1 0
	location 1 2 3
}

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