This article explains the settings and values for the Corona Legacy Material in Cinema 4D.
Overview
The Corona Legacy Material is an updated name for the Corona Material which used to be the default material in Corona 6 and older. Corona Physical Material is the new default starting with Corona 7.
In Corona 7 and newer both the Corona Physical Material and the Corona Legacy Material are available, however, the Corona Legacy Material is only kept to ensure compatibility with older scenes. In Corona 7 and newer there is no need to use the Corona Legacy Material and it is best to use the new Corona Physical Material instead.
Diffuse
Level – Specifies the diffuse level. Both the diffuse constant color and texture map are multiplied by this number. Setting 50% and using white color is equal to using 50% gray color with value 100% or using a texture map with output level 50%.
Color – This parameter specifies the basic diffuse of the material. It can be set as a constant color or mapped by a texture map.
Texture – This slot defines the texture map or shader used for the diffuse channel.
Mix mode – This parameter controls the blending mode of the texture map or shader over the diffuse color.
Mix strength – This value controls the intensity of the texture map or shader that is used.
If the Mix strength is set to 100%, the texture map or shader completely overrides the color unless the Mix mode is set to a different blending mode than Normal.
Translucency
Fraction – This parameter specifies the translucency level. Both the translucency constant color and texture map are multiplied by this number. Setting 50% and using white color is equal to using 50% gray color with value 100% or using a texture map with output level 50%.
Texture – This slot defines the texture map or shader that is used to control the fraction instead of using a single value.
Level – This is the intensity (also considered as the visibility) of the translucency.
Color – This parameter specifies the translucency of the material. It can be set as a constant color or mapped by a texture map.
Texture – This slot defines the texture map or shader that is used instead of the above color.
Mix mode – This parameter controls the blending mode of the texture map or shader over the color.
Mix strength – This value controls the intensity of the texture map or shader that is used.
If the Mix strength is set to 100%, the texture map or shader completely overrides the color unless the Mix mode is set to a different blending mode than Normal.
Reflection
Level – This parameter specifies the reflection level. Both the reflection constant color and texture map are multiplied by this number. Setting 50% and using white color is equal to using 50% gray color with value 100% or using a texture map with output level 50%.
Color – This parameter specifies the reflection of the material. It can be set as a constant color or mapped by a texture map.
Texture – This slot defines the texture map or shader that is used instead of the above color.
Mix mode – This parameter controls the blending mode of the texture map or shader over the color.
Mix strength – This value controls the intensity of the texture map or shader that is used.
If the Mix strength is set to 100%, the texture map or shader completely overrides the color, unless the Mix mode is set to a different blending mode than Normal.
Fresnel IOR
Value – This parameter controls the amount of material's reflection in a physically plausible way. Higher values create stronger reflection, setting this to 999 disables the Fresnel effect (i.e. to create a mirror-like material).
Texture – This slot defines the texture map or shader that is used to control the Fresnel IOR.
Glossiness
Value – This parameter controls how sharp or blurred the reflections are. It can be set by a numeric value or mapped by a texture map or shader. A value of 100% (white if a texture map or shader is used) gives completely sharp reflections, while a value of 0% (black if a texture map or shader is used) gives completely blurred reflections. Glossiness is the inverse of the Roughness value in some other applications.
Texture – This slot defines the texture map or shader that is used to control the glossiness.
Anisotropy
Value – This parameter specifies the Anisotropy of the glossy reflection highlights. A zero value disables the anisotropy (creates perfectly isotropic highlights). A value of -1 creates a maximally anisotropic highlight on one axis, and a value of 1 creates a maximally anisotropic highlight on the perpendicular axis. The anisotropy reference frame can be defined in the material's Advanced properties.
Texture – This slot defines the texture map or shader that is used to control the anisotropy.
Rotation of the anisotropic highlights
Value – This parameter rotates the direction of the anisotropic highlights. Value is provided in degrees.
Texture – This slot defines the texture map or shader that is used to control the rotation of the anisotropic highlights.
Refraction
Level – This parameter specifies the refraction level. Both the refraction constant color and texture map are multiplied by this number. Setting 50% and using white color is equal to using 50% gray color with value 100% or using a texture map with output level 50%.
Color – This parameter specifies the refraction of the material. It can be set as a constant color or mapped by a texture map.
Texture – This slot defines the texture map or shader that is used instead of the above color.
Mix mode – This parameter controls the blending mode of the texture map or shader over the color.
Mix strength – This value controls the intensity of the texture map or shader that is used.
If the Mix strength is set to 100%, the texture map or shader completely overrides the color, unless the Mix mode is set to a different blending mode than Normal.
Index of refraction (IOR)
Value – This parameter sets the Index of Refractions, which controls how much a ray is bent when entering the object. A value of 1 gives no bending of the ray, while the default value of 1.52 is good for generic glass. The precise value for the IOR of different materials can be found in various online references and guides.
Texture – This slot defines the texture map or shader that is used to control the IOR.
Glossiness
Value – This parameter controls how sharp or blurred the refraction is. It can be set by numeric value or mapped by a texture map or shader. A value of 100% (white if a map is used) gives completely sharp refractions, while a value of 0% (black if a map is used) gives completely blurred refractions. Glossiness is the inverse of the Roughness value in some other applications.
Texture – This slot defines the texture map or shader that is used to control the refractive glossiness.
Refraction behavior
Caustic (slow) – This option enables physically correct unbiased caustics. When off, faster transparent shadows are used.
Thin (no refraction) – When this option is enabled, it simulates a thin glass plane. Such material has no refraction and does not create caustics, making it fast to render. Use this to create windows with only a single plane, for example.
Enable dispersion – This option enables the dispersion of the refracted rays. The refractive material has a different index of refraction for different wavelengths, leading to a light dispersion effect.
Abbe number – The Abbe number is a measure of the dispersion of the material, with lower values indicating greater dispersion. For most materials, a value between 30 and 60 should be used. Values lower than 10 lead to highly unrealistic dispersion.
Opacity
Level – This parameter specifies the opacity level. Both the opacity constant color and texture map are multiplied by this number. Setting 50% and using white color is equal to using 50% gray color with value 100% or using a texture map with output level 50%.
Color – Specifies the opacity of the material. It can be set as a constant color or mapped by a texture map.
Texture – This slot defines the texture map or shader that is used instead of the above color.
Mix mode – This parameter controls the blending mode of the texture map or shader over the color.
Mix strength – This value controls the intensity of the texture map or shader that is used.
Clip – When enabled, this applies a threshold to the opacity map so that everything below 50% gray is completely opaque. This can speed up rendering significantly.
If the Mix strength is set to 100%, the texture map or shader completely overrides the color, unless the Mix mode is set to a different blending mode than Normal.
Bump
Strength – This parameter sets the intensity of the material's bump effect.
Texture – This slot defines the texture map or shader that is used for the bump effect.
Displacement
Min level – This parameter sets the displacement distance applied to areas with black (0.0) texture. Measured in world space units.
Max level – This parameter defines the strength of the displacement effect. It is the world space displacement distance applied to the areas with white (1.0) textures.
Enable water level – When enabled, this option enables the clipping of the displacement starting from the 0.0 values or black areas of the texture map or shader.
Water level – This parameter sets the clipping distance in world space units.
Texture – This parameter specifies the texture map or shader used for the displacement of the material, usually in a grayscale texture map or shader. The white values in the texture map specify the maximum displaced area, while the black values specify the minimum displaced area.
Mode – This parameter defines the mode used to calculate the displacement.
Displacement can also be manually adjusted for specific objects by using a Corona Displacement Tag.
Volumetrics
Mode – This parameter switches the volumetric medium computation of the material between volumetric scattering and subsurface scattering(SSS). Volumetric scattering is better for translucent, thin liquid, fog, or smoke-like media. SSS is better for very thick, opaque media, inside solid objects, such as skin, wax, or marble.
Absorption
Color – The absorption is controlled by setting the color that an originally white ray has after traveling the specified distance in the medium. Lower distance values make the effect stronger. A distance of 0cm is a special value that disables the effect completely. It can be set as a constant color or mapped by a texture map.
Texture – This slot defines the texture map or shader that is used instead of the above color.
Mix mode – This parameter controls the blending mode of the texture map or shader over the color.
Mix strength – This value controls the intensity of the texture map or shader that is used.
Distance – This parameter specifies the traveling distance of an originally white ray after which the ray has the Absorption color. Lower distance values make the effect stronger. A distance of 0cm is a special value that disables the effect completely.
Absorption parameters are only available if the Mode is set to Volumetric scattering.
If the Mix strength is set to 100%, the texture map or shader completely overrides the color, unless the Mix mode is set to a different blending mode than Normal.
Fraction
Value – Controls how much the material color is defined by subsurface scattering as opposed to diffuse reflection. A value of 0 results in no subsurface scattering, while a value of 1 results in full subsurface scattering and no diffuse component. It can be set as a numeric value or mapped by a texture map.
Texture – This slot defines the texture map or shader that is used to control the fraction.
Radius
Value – This parameter defines the subsurface scattering radius, i.e. how far the color scatters from a place that was hit by a light beam. It can be set as a numeric value or mapped by a texture map.
Texture – This slot defines the texture map or shader used to control the radius.
Fraction and Radius parameters are only available if the Mode is set to SSS.
Scattering
Color – This parameter defines the strength and color tint of the volumetric scattering inside the material. Setting a non-black value enables volumetric scattering/SSS effects for the material. Every time the light scatters inside the material, it gets multiplied by this value. It can be set as a constant color or mapped by a texture map.
Texture – This slot defines the texture map or shader that is used instead of the above color.
Mix mode – This parameter controls the blending mode of the texture map or shader over the color.
Mix strength – This value controls the intensity of the texture map or shader that is being used.
Directionality – This parameter specifies the directionality of scattering. A value of 0 produces isotropic (diffuse) scattering, positive values produce forward scattering and negative values produce backward scattering. The default value of 0 is suitable for most media, with the exception of clouds, where a higher positive number produces the effect of a silver lining. A value close to 1 or -1 increases the amount of image noise.
Single bounce only – When enabled, only a single bounce (direct lighting) is scattered in the medium. This results in a biased (darker) but fast rendering. Useful e.g. for rendering god rays.
If the Mix strength is set to 100%, the texture map or shader completely overrides the color, unless the Mix mode is set to a different blending mode than Normal.
Self illumination
Multiplier – This parameter controls the emission property of the material. Useful to create emissive surfaces like LED text, cellphone displays, etc.
Color – This parameter specifies the emissive color of the material. It can be set as a constant color or mapped by a texture map.
Texture – This slot defines the texture map or shader that is used instead of the above color.
Mix mode – This parameter controls the blending mode of the texture map or shader over the color.
Mix strength – This value controls the intensity of the texture map or shader that is used.
It is not recommended to use the Self illumination channel as the main light source in a scene. Use a Corona Light material instead.
If the Mix strength is set to 100%, the texture map or shader completely overrides the color, unless the Mix mode is set to a different blending mode than Normal.
Advanced
Anisotropy orientation – This parameter defines the orientation of the anisotropy highlights.
Local axis – When using this mode, the highlight direction rotates around the local object Z-axis. It sticks with the object when it is rotated/moved.
UVW – When using this mode, the highlight direction follows the direction of the U or V mapping coordinate on the object surface. The mapping channel used for this is explicitly specified.
Visibility
Visible directly – When enabled, this makes the Corona Legacy material directly visible to the camera.
Visible in reflections – When enabled, this makes the Corona Legacy material directly visible in reflections.
Visible by GI – When enabled, this makes the Corona Legacy material directly visible for GI calculation.
Visible in refractions – When enabled, this makes the Corona Legacy material directly visible in refractions.
Propagate masks – This parameter specifies the propagation of non-shading render elements (masks) after interaction with the material.
Never – Mask passes are never propagated through the material, i.e. the material is always visible in masks.
Through reflection – Mask passes are propagated through the material if reflection occurs.
Through refraction – Mask passes are propagated through the material if refraction occurs.
Always – Mask passes are always propagated through the material, i.e. the material is never visible in masks.
Invisible in masks – This mode makes the material invisible in masks.
Advanced options
Material ID – This parameter defines an ID for the material that can be used in the Corona Compositing tag or in the Corona Data shader.
Alpha mode – This parameter specifies how the objects with the material are visible in the alpha channel.
Default – This is the default mode. In this mode, the material alpha value is derived from its opacity and refract components.
Always black – In this mode, the material alpha value is black (material shows as transparent).
Always white – In this mode, the material alpha value is white (material shows as opaque).
Physical-based render (PBR) – This parameter is provided for backward compatibility, and should always be enabled, except when working with old assets. Disabled is the old (Corona 1.4 and older) and Enabled is the new (1.5+) shading mode for Corona materials. The old mode had clamped glossiness range and bright highlights on specular surfaces with a low glossiness range and no edges darkening or brightening with low glossiness, making it easier to use and compliant with emerging industry standards.
Material conversion – These options allow converting the current Corona Legacy material into a new Corona Physical material or a Corona Light material if the self-illumination channel is enabled.
Convert – Using this option converts and replaces the current material.
Duplicate – Using this option creates a new converted material without replacing the current one.