This page provides information on the LightMix tool in Cinema 4D.
Overview
IInteractive LightMix lets you adjust the intensity and color of your lights and light-emitting materials during and after render – perfect for anything from subtle adjustments to turning day into night directly from the Corona VFB. LightMix can be used on Corona EXR 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 Multi-pass, 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
- Go to the menu Corona > Multi-Pass
- Enable the Multi-pass option in the center column, then
- 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).
- 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 passes.
"Rest (unassigned)" LightMix item can be denoised and saved just like any other render pass.
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 passes) for the LightSelect pass.
Turning on Include lights not assigned to other LightSelect passes 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 pass and no LightSelect render pass has the Include lights not assigned to other LightSelect passes option enabled, these lights still end up in the Rest (unassigned) section but you aren't able to denoise the render pass 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.
| Button | Description |
| Bake currently set Lightmix colors/intensities into the scene lights. |
| Save settings of the current displayed light mix pass to a config file. |
| Load light mix settings from a config file to the currently displayed light mix pass. |
| Enables all entries if some are disabled or disables all if all are currently enabled. |
| Set all intensities to 1. |
| Set all colors to white. |
Additional Tips:
LightMix colors can be copied by dragging and dropping a color swatch onto another swatch.
LightMix colors can be reset to pure white by right-clicking on a swatch.
You can also 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!
Starting from Corona 12, with the new VFB 2.0, it is possible to create and manage multiple LightMix setups within a single render by manually adding multiple LightMix render passes.
