The Light Mix render channel provides adjustment control to the lights in the scene from inside the V-Ray Frame Buffer. When a Light Mix render channel has been added before rendering, the intensity and color of the lights and light-emitting materials can be changed directly from the VFB during and after rendering. Lights can be enabled or disabled on the go without the need to re-render your final output or navigate to individual light parameters during IPR. Furthermore, modifications made in the Light Mix can be transferred back to the actual lights in the scene with a single click. This feature can handle individual lights as easily as light groups or custom selections.

Read more about LightMix on the Chaos blog.

Create Rest Channel – Creates a Rest channel along with the other light groups. The Rest channel includes all the individual lights that are not part of any group defined by a Light Select or exceeding the limit of the list (the limit of the list is 62 individual lights or Light Selects).

Denoise – Enables the render channel's denoising, provided the Denoiser is enabled.

Tag Lightmix –When enabled, adds a flag to the light mix channel. All light selects part of the Light Mix must have light_select_in_lightmix=true. With this flag set to true it is possible to have LightSelects outside
of the LightMix.