Light groups enabled/disabled via light_mixer


Use the imager_light_mixer to adjust the contribution of certain light groups to one AOV (the output AOV). Light mixing is a process where multiple light AOVS are rendered separately. Each AOV has all of the paths that end at the camera and begin at the given lights. In a post-process, the balance or mix of those lights can be adjusted using a set of sliders, or color sliders.


  • imager_light_mixer needs to be at the top of the imager chain before any denoiser imagers, as light AOVs won't necessarily be denoised by the denoiser.
  • imager_light_mixer does not currently work properly with visible lights. This is a known limitation.
  • imager_light_mixer reconstitutes the beauty with the available AOVs, so it may overwrite the result of other imagers such as imager_white_balance for example. Workarounds would be to place the imager_white_balance after the imager_light_mixer or output the imager_light_mixer result using a prefix (it won't be white balanced).

light_mixer makes it possible to edit the contribution of light group AOVs during and after rendering

 An introduction video to the imager_light_mixer can be found here.

A scene that demonstrates how to use the imager_light_mixer can be found here.



Common

Enable

Enables the imager.

Light Mix

Light Group Manager

Opens the Light Group Manager window. Use to create, edit and delete light groups.

Reset

Restores initial values, colors and contribution states in the light mix.

On

Enables/disables the light group contribution to the imager_light_mixer.

All lights enabled. Roll over image to view left light group disabled.

 

Solo

Enables/disables solo mode for the light group. You can solo multiple lights at the same time.

solo enabled for left light group. Roll over image to view solo disabled.

Light Groups

The light group name. Default uses lights that have 'default' assigned to them as a light group. If you don't have a light group assigned to a light, Arnold assigns them the value of 'default'.

Lights groups only visible (default disabled). Rollover image to view default enabled (lights without light groups are now visible).

  

Light groups can be edited in the Light Group Manager window.


Residual Lights

residual_lights are all light contributions not coming from a light group (not listed in the light_mixer) or the Environment. A common use case for residual_lights is to control lights that are coming from a procedural and their AOV parameter is unknown or to control the lights in the scene that are not currently tweaked using another imager_light_mixer. For example, during rendering, the imager_light_mixer can be used to tweak the main lights of the scene, and residual_lights can be used to enable/disable all of the other lights.

Intensity

Intensity multiplier for the light group. Intensity controls the brightness of light emitted by the light source by multiplying the color.


Intensity: 1 (default). Roll over image to view intensity: 2.


Exposure

Exposure multiplier for the light group. Exposure is an f-stop value that multiplies the intensity by 2 to the power of the f-stop. Increasing the exposure by 1 results in double the amount of light.


Exposure: 0 (default). Roll over image to view exposure: 1.

 

Tint

Tint for the light group.


default.tint: red. Light groups have tint: white. Roll over image to view all with default white tint color.



Tint multiplies the color of the light. For example, a yellow light with a cyan tint will render as green.


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