VIEW OPTIONS LIGHT Source [Intensity/OFF]

          

This command controls the type of shading required, which light sources are to be used used and their intensity. It is used in conjunction with the VIEW HIDDEN SHADE command. Eleven independent white light sources can be used singly or in combination to illuminate the model. Each light source can be switched off, or on with specified or default intensity. Intensity is specified in the range 0.0 to 1.0.

If no options are specified the light is switched ON with its current intensity.

Below is the definition of the possible light sources with their initial defaults given ( state, intensity):

Source Comments (Default)

AMBIENT A non-directional ambient light (ON, 0.25)

EYE A parallel light source perpendicular to the screen (OFF, 0.5)

TOP A parallel light from the top of the screen at an angle of 45 degrees to the centre of the screen (OFF, 0.5)

TOP LEFT A parallel light from the top left of the screen at degrees to the centre of the screen (OFF, 0.5)

TOP RIGHT A parallel light from the top right of the screen at degrees to the centre of the screen (OFF, 0.5)

BOTTOM A parallel light from the bottom of the screen at an angle of 45 degrees to the centre of the screen (OFF, 0.5)

BOTTOM LEFT A parallel light from the bottom left of the screen at degrees to the centre of the screen (OFF, 0.5)

BOTTOM RIGHT A parallel light from the bottom right of the screen at degrees to the centre of the screen (OFF, 0.5)

LEFT A parallel light from the left side of the screen at an angle of 45 degrees to the centre of the screen (OFF, 0.5)

RIGHT A parallel light from the right side of the screen at an angle of 45 degrees to the centre of the screen (OFF, 0.5)

POSITION [/CURSOR] A parallel light which can be positioned with the

['ndc'] cursor or device coordinates such that its direction is parallel to the line from the point defined by the cursor position projected on to a sphere with its centre at the centre of the screen and diameter equal to the width of the screen, and the centre of the screen. (ON, 0.5)

Notes:

1.

Obtaining current status information
The current state of the lighting of the model can be inquired with the command UTILITY TABULATE STATUS LIGHT.

2.

Colour selection
The default colour used for a shaded view of the model is blue but a different colour can be specified as part of the VIEW HIDDEN SHADE command; for example, VIEW HIDDEN SHADE GREEN. On some displays (typically those which provide 256 colours) multi-coloured shaded pictures indicating different materials or element groups in the model can be produced by using the VIEW OPTIONS COLOUR MATERIAL or GROUP FILL command in conjunction with the VIEW HIDDEN SHADE command.

Examples:

1.

VIEW OPTIONS LIGHT LEFT

The light source at the left of the screen is switched on with its current intensity.

2.

VIEW OPTIONS LIGHT BOTTOM LEFT .3

The light source at the bottom left of the screen is switched on with an intensity of .3.

3.

VIEW OPTIONS POSITION OFF

Turns the postitionable light off.

See also the following commands

'UTILITY TABULATE STATUS LIGHT'
'VIEW HIDDEN SHADE'
'VIEW OPTIONS COLOUR'