Advanced
To optionally balance the amount of direct lighting vs indirect lighting, or even cancel direct or indirect lighting altogether, you can adjust the Direct Scale and Indirect Scale for diffuse and reflections.
Note for physically correct results both the 'Direct' and 'Indirect' lighting scales should be 1.0 or the same value.
Below shows an example of scaling down the amount of Diffuse Direct and Indirect Lighting. Diffuse GI is enabled and the base is emissive to highlight the GI indirect lighting effect. Notice how the influence of the direct light diminishes and GI indirect bounce diminishes:
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Diffuse Direct Scale: 1.0 |
0.75 |
0.5 |
0.25 |
0.0 |
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Diffuse Indirect Scale: 1.0 |
0.75 |
0.5 |
0.25 |
0.0 |
This parameter allows you to independently scale the weight of direct lighting rays, i.e. diffuse/reflection rays intersecting lights in the scene. Setting this value to 0.0 effectively disables direct lighting.
This parameter allows you to independently scale the weight of indirect lighting rays, i.e. GI/reflection rays intersecting surfaces in the scene. Setting this value to 0.0 effectively disables indirect lighting, which can be a useful optimization.
Note that setting this value to 0.0 is equivalent to the 'Specular Highlights Only' option that can be found in other Redshift material shaders, such as Architectural.
Below shows an example of scaling down the amount of Reflection Direct and Indirect Lighting. Notice how the influence of the rectangular direct lights diminishes – the lights are very hot so much lower scale values need to be used to see a noticeable effect. Indirect reflection of the surrounding scene requires less aggressive values to see a difference:
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Reflection Direct Scale: 1.0 |
0.2 |
0.1 |
0.05 |
0.0 |
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Reflection Indirect Scale: 1.0 |
0.75 |
0.5 |
0.25 |
0.0 |
This parameter allows you to independently scale the weight of direct lighting rays, i.e. diffuse/reflection rays intersecting lights in the scene. Setting this value to 0.0 effectively disables direct lighting.
This parameter allows you to independently scale the weight of indirect lighting rays, i.e. GI/reflection rays intersecting surfaces in the scene. Setting this value to 0.0 effectively disables indirect lighting, which can be a useful optimization.
Convert From Glossiness to Roughness
This option is useful when you have legacy textures that drive material roughness using the 'glossiness' convention - i.e. where a glossiness value of 0.0 means maximum roughness and a value of 1.0 means perfectly smooth. Enabling this option essentially inverts any inputs to 'roughness' parameters, to convert from glossiness to roughness.
This parameter allows you to independently scale the weight of direct lighting rays, i.e. diffuse/reflection rays intersecting lights in the scene. Setting this value to 0.0 effectively disables direct lighting.
This parameter allows you to independently scale the weight of indirect lighting rays, i.e. GI/reflection rays intersecting surfaces in the scene. Setting this value to 0.0 effectively disables indirect lighting, which can be a useful optimization.
Convert From Glossiness to Roughness
This parameter allows you to independently scale the weight of direct lighting rays, i.e. diffuse/reflection rays intersecting lights in the scene. Setting this value to 0.0 effectively disables direct lighting.
This parameter allows you to independently scale the weight of indirect lighting rays, i.e. GI/reflection rays intersecting surfaces in the scene. Setting this value to 0.0 effectively disables indirect lighting, which can be a useful optimization.
Convert From Glossiness to Roughness
This parameter allows you to independently scale the weight of indirect lighting rays, i.e. GI/reflection rays intersecting surfaces in the scene. Setting this value to 0.0 effectively disables indirect lighting, which can be a useful optimization.
Convert From Glossiness to Roughness
This option is useful when you have legacy textures that drive material roughness using the 'glossiness' convention - i.e. where a glossiness value of 0.0 means maximum roughness and a value of 1.0 means perfectly smooth. Enabling this option essentially inverts any inputs to 'roughness' parameters, to convert from glossiness to roughness.
Physically correct refraction roughness due to micro-facet theory is affected by the Index Of Refraction, where higher IOR values can yield a rougher appearance and an IOR of 1.0 would yield no roughness at all. Enabling this option ignores the IOR when generating rough refraction rays, which can result in a more predictable effect, even though it is not physically correct.
This option allows you to tune the shadow opacity of transparent materials. A value of 0.0 means the transparency of the shadow is unaffected, while a value of 1.0 means the shadow will be fully opaque and black. This option can be useful when used in conjunction with photon caustics, when a darker shadow can prevent photon caustics from appearing washed out.
Note that setting this value to 1.0 is equivalent to enabling the Enable Refractive Caustics option found on the Redshift Architectural material shader.
Below shows the effect of increasing the 'Shadow Opacity' for a tinted glass material. The shadow is from area lighting and is quite soft; as the opacity increases the shadow loses its reddish tint and the photon caustics stand out more:
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Shadow Opacity: 0.0 |
0.25 |
0.5 |
0.75 |
1.0 |
By default with this option enabled, refraction and opacity will affect the alpha channel. So if your object has 50% transparency your alpha will reflect that with 50% alpha.
Disable this parameter if you want your transparent objects to have a solid alpha.
Block Volumes In Sub-Surface Mediums
Volumetric structures, such as clouds, are not rendered where they lie within a Subsurface Scattering volume.
Energy conservation is an important feature of the Redshift Material, as it ensures physically plausible lighting for more realistic results. A material can be considered as a stack of layers, where light energy is transmitted from layer to layer, with each layer losing a certain amount of energy. For example, the amount of energy not reflected by the top-most layer (due to Fresnel) can then be refracted or diffuse. This mode lets you choose how the energy is transmitted between layers;
- "Mono" uses the luminance of the remaining energy to affect layers below. This is the mode used by other Redshift material shaders, such as Architectural.
- "RGB" uses the remaining color energy to affect the layers below. For example, if a reflection layer is pure red (1.0, 0.0, 0.0), then the energy remaining for diffuse or refraction will be (0.0, 1.0, 1.0).
Energy Conservation in Detail
Conceptually, the material can be visualized as layers like so:
- Coating
- Reflection
- Refraction / Diffuse / Sub-surface Transmission and Scattering
For physical correctness, energy is automatically conserved between these conceptual layers and between the diffuse/refraction/sub-surface layer so that the amount of light reflected is no more than received. In other words, a highly reflective material will have very little diffuse lighting or refraction/transmission.
Below shows a comparison between energy conservation modes with a tinted base reflection and grey base diffuse color. Notice how under "RGB" mode, the diffuse color takes on some of the inverse color of the red reflection tint – this is correct, because the diffuse layer gets the remaining energy that was not reflected. Notice how under "Mono" mode the diffuse color remains grey:
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Conservation Mode: RGB
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Mono |
'Overall Tint' Affects Emission
Enabling this option forces the Overall Tint to also affect the material emission color. When using the 'Overall Tint' to affect lighting (such as using ambient occlusion shader results), you should leave this option un-checked for more realistic results.
Enabling the Overall Tint Affects Emission option allows you to apply the ' Overall Tint' to the emissive part of the material. If the 'Overall Tint' is meant to just affect lighting, this option should be un-checked.
Below shows a comparison between this option being enabled and disabled, with AO driving the 'Overall Tint' of the emissive ball material. With the option enabled you can see the AO shadow affects the emissive strength of the ball material:
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'Overall Tint' Affects Emission: disabled |
Enabled |
This setting is used whenever the Trace Depth for reflections is exceeded. The color set here is then used to calculate the last reflection.
- Environment: The color is taken from an available environment or will be black, if there is no environment.
- Diffuse: The color ist taken from the diffuse (Base) color of the material
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.
The vertex attribute channel name for Tangents to drive the surface orientation for anisotropic reflections.