Advanced

This parameter allows you to independently scale the weight of direct diffuse lighting rays, i.e. rays that intersect lights in the scene. Setting this value to 0.0 disables direct lighting for the diffuse component.

In the example animation note how the white diffuse shading from light objects diminishes with low direct scale values while indirect lighting off of other objects, like the blue background, is still visible bouncing onto the underside of the shader ball. Also note the white bounce lighting from the shader ball back onto itself is still visible in the crevices with low direct scale.

This parameter allows you to independently scale the weight of indirect diffuse lighting rays, i.e. rays that intersect surfaces in the scene. Setting this value to 0.0 disables indirect lighting (global illumination) for the diffuse component, which may be a useful optimization when indirect lighting is already extremely subtle.

In the example animation below note how the blue bounce lighting on the underside of the shader ball diminishes with low indirect scale values while the white direct lighting from lights does not change. Also note the crevices on the shader ball become darker with low indirect scales because it is no longer bouncing white light back onto itself.

This parameter allows you to independently scale the weight of direct reflection rays, i.e. rays that intersect lights in the scene. Setting this value to 0.0 effectively disables direct lighting (specular reflections of lights) for reflections.

In the example animation below note how the white reflections from lights in the scene diminish with low direct scale values while indirect reflections of other objects, like the blue background, are still visible. Also note the self reflections of the shader ball are still visible even with a low direct scale.

This parameter allows you to independently scale the weight of indirect reflection rays, i.e. rays that intersect surfaces in the scene. Setting this value to 0.0 effectively disables indirect lighting (reflections of other objects) for reflections, which can be a useful optimization and is equivalent to the 'Specular Highlights Only' option that can be found in some older Redshift materials.

In the example animation below note how the blue reflections from the background diminish with low direct scale values while the white reflections from lights in the scene remain visible. Also note the self reflections of the shader ball disappear with a low direct scale.

When enabled this option inverts a glossiness input to the equivalent roughness value. This option is useful when you have legacy textures that use the glossiness convention - i.e. where a glossiness value of 0.0 is maximum roughness and a value of 1.0 is perfectly smooth, the exact opposite of the roughness convention.

Convert Gloss to Rough: Disabled Reflection Roughness:	Enabled

This setting controls what is reflected when the Reflection Trace Depth is exceeded.

• Environment: The final reflection is taken from an available environment shader (like a dome light) or will be black if there is no environment.
• Diffuse: The final reflection color is taken from the diffuse base color of the material.

When trace depths are low or an object's shape creates many self reflections this parameter can have an enormous difference on the final look. For example, the metallic shader ball in the examples below appears to glow in confined spaces when the reflection trace depth is low and End Color is set to "Environment." This is because the dome light environment is a nice bright sky reflection, once the final trace depth is reached these confined areas then reflect the bright sky even though they are primarily occluded by geometry.

Increasing the reflection trace depths can fix this issue, resulting in more realistic dark reflections, but this comes at the expense of render times - alternatively the End Color can be set to "Diffuse." Sometimes this is enough to produce a very similar darkened result to increasing the trace depths but avoids increased render times.

End Color: Environment Reflection Trace Depth: 4	Environment 32
End Color: Diffuse Reflection Trace Depth: 4	Diffuse 32

Fresnel Affects Shadow

Controls whether reflectance is taken into account when calculating a transmissive object's shadow from the following options:

• On: Fresnel reflectance is taken into account which results in more physically accurate shadow rendering, sometimes resulting in a sort of pseudo-caustic result. For most circumstances, where the heavy performance cost of caustic rendering is too great, Fresnel Affects Shadow will result in much more realistic renders in a fraction of the time. Even completely clear materials like glass cast a shadow and under certain circumstances they can be quite dark, this is because light reflected off the object may be more concentrated in some directions than others.

• On (no internal reflection) - Default: Fresnel reflectance is taken into account but internal reflections are ignored resulting in a weaker shadow overall. This setting results in more realistic shadows than the off setting without shadows that could be too dark for something like a thick pieces of glass as seen in the example images below.

• Off: Fresnel reflectance is not taken into account and the shadow of a transmissive object is controlled entirely by the Shadow Opacity parameter.

Fresnel Affects Shadow: On Shadow Opacity: 0	On (no internal reflection) 0	Off 0

In the example images below note how the shadows of the objects are brighter in the center than their edges because the fresnel reflections from the curved surface is scattering light away. Still, for the most realistic transmissive shadows Shadow Opacity should be set to 1 (resulting in a completely opaque shadow) and caustics should be used to more accurately light up the shadowed area as seen in the caustic rendering reference image below.

Fresnel Affects Shadow: On Shadow Opacity: 0	Caustic Rendering Reference Shadow Opacity: 1	Fresnel Affects Shadow: Off Shadow Opacity: 0

The effect reflections have on shadow transparency can be seen in the images below, note how the shadow becomes darker as the reflection weight is increased.

Reflection Weight: 0 Fresnel Affects Shadow: On	0.5	1

Shadow Opacity

Shadow Opacity controls the strength of transmissive shadows ranging from a value of -1 to 1, the behavior of this parameter is dependent on the Fresnel Affects Shadow option.

When 'Fresnel Affects Shadow' is set to on or on (no internal reflection):

• A value of 0.0 means the shadow is fully transparent except where reflectance has an effect on shadow transparency.

• Negative values result in transmissive shadows that become more transparent until -1 when shadows are no longer visible.

• Positive values result in more opaque shadows until 1 when a shadow becomes completely opaque.

Shadow Opacity: -1 Fresnel Affects Shadow: On	-0.3	0	0.3	1

When 'Fresnel Affects Shadow' is off:

• A value of 0.0 means the shadow is fully transparent, negative values have no effect.

• Positive values result in more opaque shadows until 1 when a shadow becomes completely opaque.

Shadow Opacity: 0 Fresnel Affects Shadow: Disabled	0.3	1

When enabled this option inverts a glossiness input to the equivalent roughness value. This option is useful when you have legacy textures that use the glossiness convention - i.e. where a glossiness value of 0.0 is maximum roughness and a value of 1.0 is perfectly smooth, the exact opposite of the roughness convention.

By default with this option enabled, refraction and opacity will affect the alpha channel. So if your object has 50% transparency your alpha channel will reflect that with 50% alpha. When disabled, the object will always have a solid alpha channel unaffected by transmission.

When enabled, volumetric objects are not rendered where they lie within a Subsurface Scattering volume.

This parameter allows you to independently scale the weight of direct sheen reflection lighting rays, i.e. rays that intersect lights in the scene. Setting this value to 0.0 effectively disables direct lighting for the sheen component.

In the example animation below note how the white sheen reflections from lights in the scene diminish with low direct scale values while indirect reflections of other objects, like the blue background, remain visible.

This parameter allows you to independently scale the weight of indirect sheen reflection lighting rays, i.e. rays that intersect surfaces in the scene. Setting this value to 0.0 effectively disables indirect lighting for the sheen component, which can be a useful optimization.

In the example animation below note how the blue sheen reflections from the background diminish with low direct scale values while the white reflections from lights in the scene remain visible. Also note the self reflections of the shader ball disappear with a low direct scale.

When enabled this option inverts a glossiness input to the equivalent roughness value. This option is useful when you have legacy textures that use the glossiness convention - i.e. where a glossiness value of 0.0 is maximum roughness and a value of 1.0 is perfectly smooth, the exact opposite of the roughness convention.

Convert Gloss to Rough: Disabled	Enabled

This parameter allows you to independently scale the weight of direct reflection rays for coat reflections, i.e. rays that intersect lights in the scene. Setting this value to 0.0 effectively disables direct lighting (specular reflections of lights) for coat reflections.

This parameter allows you to independently scale the weight of indirect reflection rays for coat reflections, i.e. rays that intersect surfaces in the scene. Setting this value to 0.0 effectively disables indirect lighting (reflections of other objects) for coat reflections, which can be a useful optimization.

When enabled this option inverts a glossiness input to the equivalent roughness value. This option is useful when you have legacy textures that use the glossiness convention - i.e. where a glossiness value of 0.0 is maximum roughness and a value of 1.0 is perfectly smooth, the exact opposite of the roughness convention.

Convert Gloss to Rough: Disabled	Enabled

Enabled by default to ensure appropriate energy conservation on surfaces with high roughness values. When disabled, high roughness surfaces lose a lot of energy which may result in a very dim look.

MMS Compensation: Enabled Metalness with high roughness	Disabled Metalness with high roughness	Enabled Transmission with roughness 1	Disabled Transmission with roughness 1	Enabled Transmission with roughness 0.5	Disabled Transmission with roughness 0.5

In order to apply the anisotropic roughness effect, the shader needs to know the orientation of the surface in u and v directions. These are the ways to specify this:

• None
• From Tangent Channel

When this option is set to None, Redshift will attempt to compute an axis automatically based on the surface normal. This can be acceptable for simple flat surfaces, but can produce unpredictable results for other types of surfaces.

The vertex attribute channel name for UVs to drive the surface orientation for anisotropic reflections.

By default the default surface UV set is used. If you require separate control from regular surface texturing, you can define a different UV set here.

The vertex attribute channel name for Tangents to drive the surface orientation for anisotropic reflections.