This article explains the settings and values for the Corona AO shader.


Overview


The Corona Ambient Occlusion (Corona AO) is a shader that can be used to color the concave and convex areas of a surface. By default, when used as diffuse color, it will darken crevices and cavities of objects while also brightening flat and raised areas. The Corona AO shader can also be used to create advanced materials, such as rusted metal, worn wood, and scratched paint, or to provide artistic control over the overall scene appearance.

 

 

Shader properties


Occluded color – This is the color that is used for occluded areas of the geometry.

Level – This is the intensity (also considered as the visibility) of the occlusion.

Occluded texture – Using this option, the occlusion can be controlled by a texture map or shader.

Texture – Defines the texture map or shader that will be used for AO.
Mix mode – Controls the blending mode of the texture map or shader.
Mix strength – Controls the intensity of the texture map or shader that is being used.

 

 


 

 

Corona AO Occluded color

 

Corona AO Occluded color - Level

 

Corona AO Occluded Texture

 

 


 

Unoccluded color – This is the color that is used for unoccluded areas of the geometry.

Level – This is the intensity (also considered as the visibility) of the color used for unoccluded areas.

Unoccluded texture – Using this option, a texture map or shader can be used to control unoccluded areas.

Texture – Defines the texture map or shader that will be used for AO.
Mix mode – Controls the blending mode of the texture map or shader.
Mix strength– Controls the intensity of the texture map or shader that is being used.

 

 


 

 

Corona AO Unoccluded color

 

Corona AO Unoccluded color - Level

 

Corona AO Unoccluded Texture

 


 

Max distance – This is the distance used for the transition between occluded and unoccluded areas.

Max distance texture – Using this option, a texture map or shader can be used to control the transition between occluded and unoccluded areas.

Texture – Defines the texture map or shader that will be used for AO.
Mix mode – Controls the blending mode of the texture map or shader.
Mix strength – Controls the intensity of the texture map or shader that is being used.

 

 


 

 

Corona AO Max distance

 

Corona AO Max distance texture

 

Corona AO Max distance texture (Mix strength)

 


 

Color spread – Makes the effect of occlusion stronger and more apparent when using higher values.

Ray directionality – Controls the distribution of the rays around the object's normals. Lower values result in uniform ray distribution around the geometry normals. Increasing this value causes the rays to focus on the occluded areas only.

Max samples – Controls the number of samples used to calculate AO. Increasing the number of Samples provides a cleaner render (less noise) in a shorter time at the cost of other effects such as GI and anti-aliasing. Lower values render faster but look noisier. 

Usually, there is no need to change the default value.

Calculate from – Provides different calculation methods for the AO.

Available modes to calculate the AO:

Inside – Considers occlusion looking from the inside of the object (back-facing surface).
Outside – This mode is enabled by default, and it creates occlusion by looking at the object from its outside (front-facing surface). This is similar to illuminating an object with environmental lighting.
Inside + Outside – Calculates both modes at once and merges them.

Direction offsets – These values control the axis where the rays are going to be distributed. From left to right, X, Y, and Z axis can be used separately or combined.

Include/Exclude – A list of scene objects that can be used to include or exclude specific objects from being considered for AO calculations.

Available modes for the include/exclude list:

No exclusions – This mode is selected by default and disables the use of the include/exclude list.
Use include list – This mode considers only the objects in the list for AO calculation.
Use exclude list – This mode excludes only the objects in the list from AO calculation.
Only other objects occlude – This mode considers only the...
Only the same object occludes – This mode only considers the...

Include children – When enabled, it includes nested objects (children objects) from those specified in the above list.

 

 


 

 

Corona AO Color Spread

 

Corona AO Ray directionality

 

Corona AO Max samples