World Light Source

A world light is an infinitely remote light source casting orthographically projected beams onto the scene. The shadows cast by this light are parallel, which provides a realistic simulation of the sunlight.

World light shadows has an adaptive bias that is adjusted automatically on shadow maps applying: depending on the slope angle of the world light and its resolution, an offset of the depth value stored in the shadow map is calculated.

See Also#

To add a world light to the scene via UnigineEditor, do the following:

1. Run the project with UnigineEditor.
2. On the Menu bar, click Create -> Light -> World.

   

3. Place the world light somewhere in the world.
   Notice

   The physical position of the source is not important, only the direction matters, as it defines the shadow casting orientation. To change the light's direction use the rotation manipulator.
4. Adjust the world light's settings.

The following set of options is available for the world light in the Node tab of the Parameters window. It includes both the common parameters and the parameters specific for the world light source. The specific ones are described below.

Light Settings#

Disable Angle

The angle between the light source and the zenith at which the light source is disabled (shadows and the diffuse component is disabled). However, the light source still affects scattering.

Scattering

A lighting type: None — render the atmosphere as if there were no global lights, that is, there will be no sky color gradient in any direction. Sun — render the atmosphere in accordance with the Sun's lighting. Moon — render the atmosphere in accordance with the Moon's lighting. Notice Light scattering is defined by a combination of environment scattering LUTs (Look-Up Textures) describing different states of the sky during the day. The atmosphere is rendered based on interpolation between these LUTs. Scattering = Sun Scattering = Moon

Shadow Settings#

Shadows	Enables or disables the PSSM technique.
Cascade Mode	Shadow cascade generation mode to be used (available for Static light mode only): Dynamic — In this mode shadow cascades are built dynamically relative to the camera position making it possible to change the time of day (day-night cycle). Static — In this mode shadow cascades are built relative to the light source position and baked. This mode is suitable as a performance optimization technique for small-area ArchViz projects where shadow cascades can be divided into 2 sections: walkable area with high-resolution shadows (as they're observed closely) and non-walkable area with low-resolution shadows (as they're observed from a distance). Notice Changing the time of day is not available in this mode, as shadow cascades are baked.
Resolution	Size of the shadow map that defines shadow quality.
Number of cascades	A number of cascades with different shadow maps. Each cascade requires a separate rendering pass. All the shadow maps have the same resolution (the Shadow resolution parameter value), but are applied to different cascades. Thus, close-range shadows are of higher quality and distant ones of lower. The minimum number of cascades is 1, the maximum is 4. Increasing the number of cascades enhances the rendered image quality. However, at that, performance efficiency drops. Notice To visualize the cascades, enable Helpers -> Shadow cascades. In Static cascade mode, shadow cascades are additionally visualized by the boxes that define the shadow area. Cascade Mode: Static Cascade Mode: Dynamic
Cascade border	A multiplier for the distance to the border of the cascade in range [0;1]. Distance to the border depends on the Cascade Mode and is set as follows: For Dynamic mode — corresponds to the Shadows Distance value and is measured from the Camera position. For Static mode — is defined by the dimensions of the shadow area box projection and measured from the World Light position. The number of cascade borders depends on the number of cascades: For one cascade, there is no cascade border. For 4 cascades, there are 3 cascade borders (for the first three cascades). For the last cascade, the multiplier is always 1. Setting the cascade borders allows you to accurately adapt the quality of the shadows depending on their remoteness from the viewer. Decreasing the multiplier value makes the cascade smaller, more compact positioned and covering less distance. At the same time, the resulting shadow is of a higher quality. Increasing the multiplier value makes the cascade larger with broader coverage of the area. Cascade border 0 = 0.02 (shadow of higher quality) Cascade border 0 = 0.1

Enabling Static Cascade Mode makes extra parameters available. In addition to the static shadow parameters common for all light sources, there are parameters that define the size of the box within which the static shadows are rendered:

Height	Size of the shadow area box along the X axis.
Width	Size of the shadow area box along the Y axis.
ZFar	Distance from the light source position along the light direction vector. Notice Ensure that ZFar distance is big enough to have both objects and surfaces that take shadows within the shadow area box.