Basic Library Version: 16

Sky Object

  1. General Description
  2. Parameters
  3. Usage

1. General Description

Sky Object is used to simulate the diffuse light effect of the sky for photorendering. It consists of distant lights distributed in a hemispherical array.

The object has two working modes: 'Quick Method' and 'Realistic Method'. In the 'Quick Method', the object places LWA_LIdistant light sources (see original documentation and parameter mapping) distributed in a hemisphere. In 'Realistic Method' only one LWA_LIgssky light source is placed.

2. Parameters

The input parameters of this object are:

Name Type Default Affects Description
A Length 1 2D / 3D Not used
B Length 1 3D Not used
C Boolean 1 3D Switch on / off the light source
D RGB 0.81 3D Red colour component
E RGB 0.89 3D Green colour component
F RGB 0.99 3D Blue colour component
G Intensity 50 3D Intensity of the Sky Light
ZZYZX Length 1 - Not used
AC_show2DHotspotsIn3D Boolean 0 - Not used
gs_sky_type String "Quick Method" 3D Rendering type: 'Quick Method' / 'Realistic Method'
gs_lwa_lattitude_res Integer 3 3D The number of latitudinal lines used in placing light sources in 'Quick Method'. Available values: >=1
gs_lwa_longitude_res Integer 6 3D The number of longitudinal lines used in placing light sources in 'Quick Method'. Available values: >=3
gs_lwa_num_lights Integer 11 - Informs the user from the number of generated light sources in 'Quick Method'.
gs_lwa_cast_shadows Boolean 1 3D Shadow casting on / off.
gs_lwa_soft_shadows Boolean 1 3D Shadow softness on / off. Affects 'Quick Method' only.
gs_lwa_shadow_quality Integer 2 3D Quality of the shadows. Available values: 0 - 5. Affects 'Quick Method' only.
gs_lwa_set_sun_position Boolean 0 2D / 3D Set Sun Position Manually. Affects 'Quick Method' only.
gs_lwa_sun_azimuth Angle 0 2D / 3D Sun Azimuth - If gs_lwa_set_sun_position = 0 then this parameter uses the GLOB_SUN_AZIMUTH global. Affects 'Quick Method' only.
gs_lwa_sun_altitude Angle -1 3D Sun Altitude - If gs_lwa_set_sun_position = 0 then this parameter use the GLOB_SUN_ALTITUDE global. Affects 'Quick Method' only.
gs_numSamples Integer 50 3D Number of samples - used in 'Realistic Method'.
gs_cont_pen Pen 10 2D / 3D Object contour pen

Longitudinal and Latitudinal Resolution

Longitude and latitude resolution parameters are used to specify the number of the generated light sources to represent the sky.
Latitude resolution equals the number of latitudinal lines on the hemisphere.
Number of longitudinal lines is measured on the first latitudinal line (the nearest to the equator). The number of longitudes (eg. light sources) along the rest of the latitudinal lines is decreased to guarantee the equal light distribution.

Sample position of lights

Soft and Hard Shadows

This parameter is used to specify whether hard-edged shadows or soft-edged shadows are created. Effective if gs_lwa_cast_shadows is on.

Shadow Quality

The parameter defines the quality of the soft shadows cast by the sky. Available values are integer numbers in the range [0 - 5]. The default is 2. It maps the following LightWorks® shader arguments:

3. Usage

Place the Sky Object just anywhere in the plan.

Note, that the integrated LightWorks® rendering doesn't give a proper image quality in case the 3D data stucture is generated from a selection (e.g. with the Arrow Tool or with the Marque Tool) and this selection doesn't contain the Sky Object.

The LightWorks ® API is copyright (C) 1999,2000-2004 LightWork ® Design Ltd. All Rights Reserved.