Extra Buffers

These are buffers which shading system elements, such as the Material nodes and Shading Models, provide.
Most buffers are available here in direct and indirect versions. The "direct" buffers contain data from direct illumination of the surface, meaning the light that came directly from a light source. As opposed to the indirect buffers which contain data from the indirect illumination, that being light that got to the surface via an indirect route such as light that has bounced off another object via radiosity. Some buffers only become available when the materials pertaining to them are used.

Carpaint	Skin	PBSDF

Carpaint, Skin and Principled BSDF have several entries in the Extra Buffer list below

New to 2019

For most of the extra buffers listed here, there are two additional buffers available, labeled as Rho and Weight. Rho contains a shaded visual showing the percentage of the buffer's effect in the render. For example, a specular_rho buffer would provide the amount of reflection occurring based on the way in which reflection changes with glancing angles, fall off and so forth. Weight contains the value of the surface shader setting in this buffer. In our example, a surface of an object with a constant 50% value for specularity would appear as a 50% grey values across the entire object in the buffer. If a texture drove the specular value, we would see the texture values instead.

They are intended for heavy compositing work and used to extract, for instance, the color from a specular buffer; by dividing the Rho by the specular direct and indirect to get the raw untinted reflection value.

Buffer	LDR	HDR
Clearcoat Direct Provided by the Carpaint material node, is the contribution of its Clearcoat element from direct illumination
Clearcoat Indirect Provided by the Carpaint material node, is the contribution of its Clearcoat element from indirect illumination
Clearcoat Rho xxx
Clearcoat Weight xxx
Dermis Direct Available when the Skin node is used
Dermis Indirect Available when the Skin node is used
Diffuse Direct Provided by many material nodes, is the diffuse shading from direct illumination
Diffuse Indirect Provided by many material nodes, is the diffuse shading from indirect illumination
Diffuse Rho xxx
Diffuse Weight xxx
Epidermis Direct Available when the Skin node is used
Epidermis Indirect Available when the Skin node is used
Fog The diffuse color of objects with no other component	Fog is visible in the Alpha component of the image in Image Viewer
Hypodermis Direct Available when the Skin node is used
Hypodermis Indirect Available when the Skin node is used
Legacy Volumetric Shows legacy HyperVoxels separately The left image shows a final render with a surface HyperVoxel cloud, the second image shows the Legacy Volumetric buffer
Luminosity Only shows elements that have luminosity
Raw RGB The Diffuse color without additional surface components.
Reflection Only shows pure reflection. If PBSDF has zero roughness on reflection, it shows in the reflection buffer (as a scalar represented by changes to the alpha, whereas Standard appears as a color) The dragon (PBSDF) is visible in this buffer in Image Viewer using the mouse to show the changing alpha, but not in a PNG. The ball is surfaced with Standard
Refraction Only shows elements that have a refractive component. For this buffer we changed the dragon to use the Dielectric material
Refraction Rho xxx
Refraction Weight xxx
SSS Direct Provided by nodes with a SubSurface Scattering component, is the Subsurface Scattering contribution from direct illumination
SSS Indirect Provided by nodes with a SubSurface Scattering component, is the Subsurface Scattering contribution from indirect illumination. The green glow in this buffer is caused by the luminosity in the edges shown in the final render at the top of the list
Shadow Indicates scene shadows
Sheen Direct Provided by nodes with a Sheen component, is the Sheen contribution from direct illumination	Sheen is visible in the Alpha component of the image in Image Viewer
Sheen Indirect Provided by nodes with a Sheen component, is the Sheen contribution from indirect illumination	Sheen is visible in the Alpha component of the image in Image Viewer
Sheen Rho xxx
Sheen Weight xxx
Specular Direct Provided by many material nodes, is the Specular contribution from direct illumination
Specular Indirect Provided by many material nodes, is the Specular contribution from indirect illumination
Specular Rho xxx
Specular Weight xxx
Translucency Direct Provided by Standard, is the Translucency contribution from direct illumination	Translucency is visible in the Alpha component of the image in Image Viewer
Translucency Indirect Provided by Standard, is the Translucency contribution from indirect illumination	Translucency is visible in the Alpha component of the image in Image Viewer
Translucency Rho xxx
Translucency Weight xxx
Volumetric Direct Provided by the Volumetric system, is the volumetric's contribution from direct illumination	Volumetric Direct is visible in the Alpha component of the image in Image Viewer
Volumetric Emission Provided by the Volumetric system, is the volumetric's emission of light into the scene	Volumetric Emission is visible in the Alpha component of the image in Image Viewer
Volumetric Indirect Provided by the Volumetric system, is the volumetric's contribution from indirect illumination	Volumetric Indirect is visible in the Alpha component of the image in Image Viewer
Volumetric Light xxx
Volumetric Transmittance xxx

Carpaint, Skin and Principled BSDF have several entries in the Extra Buffer list below

Fog is visible in the Alpha component of the image in Image Viewer

The left image shows a final render with a surface HyperVoxel cloud, the second image shows the Legacy Volumetric buffer

The dragon (PBSDF) is visible in this buffer in Image Viewer using the mouse to show the changing alpha, but not in a PNG. The ball is surfaced with Standard

For this buffer we changed the dragon to use the Dielectric material

The green glow in this buffer is caused by the luminosity in the edges shown in the final render at the top of the list

Sheen is visible in the Alpha component of the image in Image Viewer

Sheen is visible in the Alpha component of the image in Image Viewer

Translucency is visible in the Alpha component of the image in Image Viewer

Translucency is visible in the Alpha component of the image in Image Viewer

Volumetric Direct is visible in the Alpha component of the image in Image Viewer

Volumetric Emission is visible in the Alpha component of the image in Image Viewer

Volumetric Indirect is visible in the Alpha component of the image in Image Viewer