Default Lights– Enables the usage of the default lights when there are no light objects in the scene or when you have disabled lighting globally with the Use Lights parameter.
Shadows– Enables shadows globally.
Disable Light Materials Illumination – When enabled, all self-illuminated materials used in the scene will not render.
Light Evaluation Mode – Determines how lights are sampled in scenes with many lights. For more information, see the Adaptive Lights example below.
Full Lights Evaluation – V-Ray goes through each scene light and evaluates it at each shading point. In scenes with many lights and lots of GI bounces, this leads to a lot of shadow rays being traced and rendering can become extremely slow. When GPU rendering, this introduces probabilistic light calculations but does not allow the Number of Lights parameter to be set. Older V-Ray scenes with the Probabilistic Lights parameter disabled, will default to using this option. Light Tree – V-Ray selects a variable number of suitable finite light sources based on proximity and evaluates only those. This mode may speed up the Light Cache and Brute Force calculations for scenes with lots of lights. It can also reduce flickering due to missed light sources.
Adaptive Lights – Uses information from the Light cache to determine which lights to sample. If a Light cache is not used, light tree sampling is used. Depending on the scene, it can be faster than the Full lights evaluation mode. For more information, see the Adaptive Lights example below.
Number of Lights – Number of lights from the scene that are evaluated by V-Ray when the Light evaluation parameter is to either Adaptive or Uniform Probabilistic. To achieve a positive effect from probabilistic light sampling, this value must be lower than the actual number of lights in the scene. Lower values make the rendering go faster, but the result is potentially more noisy. Higher values cause more lights to be computed at each hit point, thus producing less noise but increasing render times.
Consistent Lighting Elements – When enabled, this option provides more accurate, artifact-free lighting render elements not dependent on light sampling. It also provides better support for Adaptive dome light.
UI Text Box
type
note
Since V-Ray Next, some of the render elements are rendered differently than before. The Lighting render element now contains all direct diffuse illumination and the GI element contains all indirect diffuse illumination. Similarly, all direct reflections of lights now go to the Specular element and all indirect reflections go to the Reflection element.
Expand
title
Read more...
Previously this behavior depended on the sampling of the lights and not just on the type of the contribution. Some of the direct contributions that should be in the Lighting and Specular elements were written to the GI and Reflection elements instead. In both cases they compose back to Beauty correctly but the different types of contributions are now split between the elements more consistently.
This change makes the elements more consistent but it's also needed for preventing artifacts in these elements with the adaptive dome light (and possibly in the future with other adaptive lights).
The raw elements are affected only when the corresponding normal and filter elements are available, otherwise they're rendered as before. This is because the raw elements have to be derived internally from the corresponding normal elements in order to work with the consistent elements (fe.eg. VRayRawGlobalIllumination = VRayGlobalIllumination / DiffuseFilter).
There's an option to enable or disable the new behavior in the Global Switches rollout under the V-Ray tab in the Render Setup window. The consistent elements are automatically enabled when the scene contains an adaptive dome light so they don't have artifacts. They are also enabled by default for new scenes. For V-Ray GPU they are always enabled without an option to disable them.
LightSelect Metadata – When enabled, writes LlightSelect RE metadata to image headers if supported by the file format.
