Table of Contents

This page provides information on the LightMix tool in Cinema 4D.



Interactive LightMix is unique to Corona Renderer and lets you adjust the intensity and color of your lights and light-emitting materials during and after rendering.

This is perfect for anything from subtle adjustments to turning day into night directly from the Corona VFB.

LightMix can be used on Corona EXR (.cxr) files outside of any 3D software using the Corona Image Editor.


Where to find the LightMix?

LightMix can be set up either automatically, or manually.

Setting up LightMix automatically

Go to the menu Corona > Multi-Pass, then enable the Multi-pass checkbox in the center column, click on the Multi-pass element, and finally press the Setup Interactive LightMix button.

Corona Interactive LightMix Setup dialog then pops up, allowing you to:

  • Choose the way lights are grouped - based on instances, groups, or individual lights
  • See how much RAM is used by each LightMix layer (calculated depending on the resolution of the final render)
  • Decide whether hidden lights should be also considered by the LightMix setup
  • Decide whether denoising should be applied to all LightMix and LightSelect passes



Once the settings are confirmed, click the Generate button and:

  • One Interactive LightMix pass is automatically added to enable the LightMix tab in the Corona VFB
  • Multiple LightSelect passes are automatically added depending on the number of lights (including Corona Sky and Corona Sun objects if they're present in the scene) - this allows changing the color and intensity of each scene light

The available options for the automatic LightMix setup are:

  • Instanced lights – If there are instanced lights in the scene, each group has its separate pass. All unique lights in the scene are stored in their individual multipass.
  • Individual lights – Lighting information of each light is stored in a separate multipass.
  • Grouped lights – Lighting information of each group of lights is placed in a separate pass. All lights that are not attached to any group in the scene are stored in their individual multipass.
  • Layers – Lighting information for each layer is stored in a separate multipass.




After using this one-click solution, you can start rendering the scene (both regular and Interactive Rendering will work), and then go to the LightMix tab in the Corona VFB to change the intensity and color of each light.




Set up LightMix manually

  1. Go to the menu Corona > Multi-Pass
  2. Enable the Multi-pass option in the center column, then
  3. From the LightMix category on the left panel, open it and Add the LightMix pass (this is required to enable the LightMix option in the VFB).
  4. Finally, add as many LightSelect passes as required (this is required to be able to control a scene light or environment light).

Each light that you wish to control should be added to the Include specific light sources list in each LightSelect pass. You can add one or more lights to each LightSelect pass.

Additionally, you can enable the Include children checkbox if you have grouped or nested light objects.

Objects using the Corona Light Material with the Emit light option disabled, cannot be added to a Lightselect pass. Equally, the same applies to objects using a material with the self-illumination channel enabled.

It is suggested to organize the lights using fewer LightSelect passes instead of using one LightSelect pass for each light in the scene.



LightMix and Denoising

You can decide whether denoising should be applied to each LightSelect pass or not. To denoise the whole LightMix output, you must turn on the denoising option for all LightSelect passes.

Denoising can be enabled manually for each of the LightSelect passes.




Denoising can be also enabled automatically for all LightSelect passes using the Included in denoising checkbox in the Corona Interactive LightMix Setup dialog.

Denoising can be enabled automatically for all of the LightSelect elements.




"Rest (unassigned)" LightMix item can be denoised and saved just like any other render element. 

This is achieved by allowing any LightSelect pass to act as the Rest (unassigned) pass by enabling the appropriate option (Include lights not assigned to other LightSelect elements) for the LightSelect pass.

Turning on Include lights not assigned to other LightSelect elements allows saving and denoising the LightMix pass with lights not included in other LightSelect passes. This pass is denoised just like other any other LightSelect pass as long as the Apply denoising option is enabled.

If any lights are left unassigned to any LightSelect render elements and no LightSelect render element has the Include lights not assigned to other LightSelect elements option enabled, these lights still end up in the Rest (unassigned) section but you aren't able to denoise the render element or save it.



Usage Workflow

After setting up LightMix (either automatically, or manually), the color and intensity of each light can be adjusted in the VFB. Go to the LightMix tab in the Corona VFB and change the desired parameters - this can be done during, or after rendering, for both regular and interactive rendering. You can also use additional buttons below the lights list.

>Scene - This button bakes all LightMix colors and intensities into the scene lights. After clicking this and confirming, the image displayed in the VFB is temporarily changed to the non-LightMix version, and you need to re-render it to get the desired result. Instanced lights become unique in case some of them were separately altered using the LightMix.

Save... / Load... - These buttons save a LightMix preset as a .conf file. This is useful, for example, when creating day and night versions of a scene. It is also possible to load a preset after a camera is changed and a different view is rendered. The .conf files can be also loaded into the Corona Image Editor.

Toggle all - This button enables or disables all lights in the LightMix list.

All 1.0 - This button reverts all LightMix layers' intensities to 1.0, which means the values set in the scene are used - this does NOT make all lights equally bright if they have different intensities set in the scene.

All white - This button reverts the colors of all LightMix layers to pure white, which results in having the initial colors of the light objects used.

You can right-click on the light names on the LightMix list in the Corona VFB to select a specific light in the scene, add that light to the current selection, or remove that light from the current selection.



Compositing LightMix Layers in Other Applications

To compose different LightMix layers (LightSelect passes) so that the final image looks the same as in the Corona VFB open the layers in the application of your choice, and stack them on each other in any order using the Add blending mode. In Adobe Photoshop it is called Linear Dodge (Add).



Using LightMix with Multiple Suns and Environments

It is possible to add multiple suns and skies to your scene, and then control their appearance with LightMix. This means that you can render just once, and pick between completely different lighting conditions, adjust sun and environment intensity and color, and even have two or more suns illuminate your scene at a time. No re-rendering needed!