This simulates light from a hemisphere or dome above the scene, representing the sky. It can also be used with high dynamic range (HDR) images to perform image-based environment lighting. This is the node which is typically used for lighting exterior scenes.
This light is designed for outdoor scenes and is represented by a spherical dome in the background. Importance sampling will trace rays to specific directions of this dome. However, in an interior scene, most of these rays will hit an object, getting no contribution from the light at all and thus creating noise. In this situation, adding light_portals to the windows will help to reduce noise in an interior scene when using the skydome_light.
As well as the settings that are common to all lights (except for Decay), the Skydome also has:
The resolution controls the detail of reflections of the skydome. For most accurate results the Skydome light resolution must be set to match the HDRI image resolution, however, in many cases it can be set lower without a noticeable loss of detail in reflections. By default, the parameter is set to 1000. The higher the resolution parameter, the longer the skydome_light will take to precompute the importance tables for the light, which increases scene startup time.
The type of map being connected. It can be set to Lat-long (most common), Mirrored Ball or Angular.
Per-light scaling for transmission. Should be left at 1 to produce physically accurate results.
Diffuse / Specular / SSS / Volume
Per-light scaling for Camera, Transmission, Diffuse, Specular, SSS, Indirect and Volume. Weights scaling the light contribution to each of those components independently. Should be left at 1 to produce physically accurate results.
Only Area lights and Point lights (non-0 radius) are visible to the camera. Camera and Transmission values default to 0 with Area lights.
KtoA defaults to camera=0 so that a background can be composited afterwards (this preserves traditional Katana workflows).
- off: turns off portals.
- interior_only: blocks any light outside portals for interior only scenes.
- interior_exterior: lets light outside portals through for mixed interior and exterior scenes.
An additional shader slot for background rays.