Next to lighting from the background and any object with an emission shader, lights are another way to add light into the scene. The difference is that they are not directly visible in the rendered image, and can be more easily managed as objects of their own type.
Light settings for all renderers.
Specular Light intensity multiplier. Use it for more artistic control. Setting this to anything but 1.0 will yield non-photorealistic result.
- Custom Distance
If enabled uses Distance as the custom attenuation distance instead of global light threshold. In order to avoid long setup times, this distance is first computed automatically based on a light threshold. The distance is computed at the light origin and using the inverse square falloff.
Specifies where light influence will be set to 0.
The light's Power/Strength affect both specular and diffuse light.
- Clip Start
Distance from the light object at which the shadow map starts. Any object before this distance will not appear to cast shadows. Clip Start will only appear for point, spot and area lights.
- Bias (バイアス)
Bias applied to the depth test to reduce self shadowing artifacts.
This type of shadow exists to fix light leaking caused by bias or shadow map undersampling. It uses the depth buffer to find occluders (just like Screen Space Reflections). However, just like Screen Space Reflections it has the same limitations, namely, unknown object thickness and effect disappearing at screen edges.
The distance of action of Contact Shadows should remain quite small. They are not accurate enough to shadow the entire scene.
World space distance in which to search for screen space occluder.
- Bias (バイアス)
Bias applied to the ray tracing to reduce self-shadowing artifacts.
Pixel thickness used to detect occlusion, treating any potential occluder as this thick.
Cascaded Shadow Map
These special kind of shadow maps are used by Sun lights. This is because they can shadow large scenes by distributing multiple shadow maps over the frustum range. Each cascade covers a different portion of the view frustum. Do note that cascade shadow maps are always updated because they are view dependent. This means they have a high performance impact.
In orthographic view the cascades cover the whole depth range of the camera with an evenly distributed shadow precision.
Number of cascades to use. More cascades means better precision but a lower update rate.
Fade transition area between two cascades. Higher values means less overall resolution because cascades need to overlap.
- Max Distance
Distance away from the view origin (or camera origin if in camera view) to cover by the cascade. If the view far clip distance is lower than Max Distance, the view far clip distance will be used. Only works in perspective view.
- Distribution (分布)
Puts more resolution towards the near clip plane. Only works in perspective view.
Unlike in Cycles, the Size of spot lights does not change the softness of the cone.