Render settings explained - Corona Renderer for C4D


As opposed to most other renderers, in Corona there is usually no need to change any render settings. In most scenes the defaults will work great, guaranteeing best quality and rendering speed possible. If you would like to understand what each render settings does, below you will find short descriptions of each one of them.


To access Corona render settings go to Render > Edit Render Settings..., or press Ctrl+B, then make sure that Corona is selected as your active renderer.


Note: once any setting is changed, it can be reverted to the safe default value by right-clicking on its spinner. 




Render Settings > Corona > General settings


Progressive rendering limits

By default, rendering in Corona is indefinite - it never stops unless "cancel" or "stop" button is pressed. You can use these limits to automatically stop rendering after given time, pass amount, or noise threshold.

See: How to limit rendering?



Global illumination

Here you can change the primary and secondary GI solvers. A rule of thumb is:

  • For interiors - use "Full (multiple bounces)" as the GI mode, and UHD Cache as the GI solver.
  • For exteriors - use "Full (multiple bounces)" as the GI mode, and Path tracing as the GI solver. 



Render overrides

Render hidden lights - toggles rendering of hidden lights. Useful when rendering isolated objects.


Render only masks (disable shading) - this enables rendering for mask passes only, and skips rendering of beauty-dependent passes. Useful for quickly rendering masks without the need to spend time on other passes.


Mtl. override - this enables the override material, which will be applied to all scene objects. Useful for creating "clay renders" - usually for debugging problematic scenes.



Denoising

Denoising controls.

See: How to use denoising?




Render Settings > Corona > Camera/Postprocessing


Tone mapping

Here you can enable the simple (EV-based) exposure controls.



Basic photographic settings

Here you can enable the photographic exposure controls (ISO, shutter speed, f-stop). The "sensor width" value also affects the depth of field effect.



LUT

Allows for appplying a specific LUT to the rendered image.



Bloom and glare

This controls bloom and glare appearance in the rendered image.

Bloom is a soft, bigger glow around bright objects. Glare is a smaller, sharp, flash effect.



Sharpening

Sharpen and blur controls.

Sharpen and blur can be used together to get rid of the "pixel-perfect" noise. The default values work well. 



Depth of field

This allows for toggling and controlling the depth of field effect.

Depth of field is also dependent on camera settings such as F-stop, sensor size, and target position.



Motion blur

This allows toggling and controlling the motion blur effect.

Motion blur is also dependent on the camera shutter speed. 




Render Settings > Corona > Scene environment


Scene environment

Here you can set custom scene environment - it will override any currently used native C4D environment.



Environment overrides

Direct visibility, reflections, and refraction overrides - used to enable custom environment maps.



Volume

This controls the material used as global volume (volumetric fog).




Render Settings > Corona > Performance settings


Basic configuration

Lock sampling pattern - locks the "noise pattern" for each rendered frame. Sometimes it is necessary to disable this setting - for example when denoising animations in 3rd party post processing software. Leave this enabled when using Corona's denoising.



Sampling balance

GI and light sampling settings. Should not be changed unless absolutely necessary, and provided that the user is fully aware of what he is doing.


GI/AA balance - the number of AA samples used per pass.


Light samples multiplier - the number of samples used for direct light.


If GI/AA balance is set to 16, and LSM is set to 2, it means that per one pass 16 samples will be used for the GI, and 32 samples will be used for direct lighting (2 x 16).  



Speed/Accuracy balance

Max sample intensity - lower values will reduce noise, but also make the image less realistic and darker. Higher values will introduce noise, and make the image slightly more realistic. Value of 0 means that this setting is disabled, and the rendering is unbiased. The default value of 20 should be always used.


Max ray depth - controls the maximum amount of reflections and refractions rendered. Increasing or decreasing this value has almost no effect on the rendering speed or quality, so it is strongly advised to use the default value of 25. 



Displacement

Displacement settings. In most cases "screen size" should be enabled. The default value of 2px should work well.

In case of visible flickering, or other problems, "world size" can be enabled. The world size value is dependent on scene scale and other factors - this is the smallest allowed detail size in the scene displacement. Too high displacement settings may result in excessive RAM usage.



Interactive rendering (not yet supported in the beta releases!)

Max passes - controls how many passes may be rendered with IR


Clear VFB inbetween passes - whether or not to clear the VFB upon scene update




Render Settings > Corona > Development / Experimental stuff

These settings are only available if "Enable devel/debug mode" is checked under Corona > Preferences.

This is used only for debugging and testing unfinished features of Corona Renderer. This should never be changed, unless the user is explicitly asked to do so. Changing the values here may result in incorrect and extremely slow rendering, or cause other problems.




Render Settings > Corona > Frame buffer settings


Frame buffer

Clear VFB inbetween renders - whether or not the VFB should be cleared between each next rendering. 


Render stamp - toggles the render stamp. It is baked into the saved image. The stamp contains useful information such as Corona version number, render time, and other statistics. The render stamp can be enabled or disabled interactively during and after rendering. 

See: Renderstamp variables


Image filter

Image filtering settings. These should not be changed, unless absolutely necessary.




Render Settings > Corona > Secondary GI: UHD Cache

For a more detailed guide, see: how to use UHD Cache? 


Preset - "Still frame" preset should be used for stills. "Animation" preset should be used for animations to prevent flickering or other possible issues.


Precision - lower values mean faster precomputation and more bias. Higher values mean slower precomputation and more realism. The default value works well and should not be changed.


Do previz - toggles the pre-rendering visualization of the UHD Cache calculations


Save/Load

Precomputation:

Calculate from scratch - calculates a new cache each time rendering is started - the default setting, useful for still images.

Load from file - loads a specified cache file and uses it for rendering - useful for rendering animations without moving objects or lights. 

Load from file + append - loads a specified cache file and uses it for rendering; new information will be calculated for the cache and stored in it, if needed - useful for animations with subtle object or light movement.


After render:

Discard - discards any computed cache after the rendering is finished.

Save - saves the computed cache to a specified file. 


Filename - specifies where the UHD Cache file should be saved, or where it should be loaded from.



Render Settings > Corona > Team render

Team render settings.