This page gives some basic details about the Color Channel render pass and what you can do with it in Houdini.
The Color Channel is a container node that allows the output of almost every render channel available in V-Ray. It allows you to extract different color components from the image (i.e. Diffuse, Reflections, Refractions, etc.) to use later for tasks like compositing.
||out Network|| > V-Ray Render Elements node > V-Ray > Render Channel > Color Channel
||mat Network|| > V-Ray > Render Channel > Color Channel
The parameters for this render channel appear in the Parameters tab under the out Network and within the render channels node.
Type – Allows you to select which color information to extract from the image as a separate channel. For more details, please see the Channel Types table below.
Name – The text added to the end of the rendered file, when saved as a separate file (e.g. myrender.colorchannel.vrimg).
Deep Output – Specifies whether to include this render element in deep images.
Color Mapping – When enabled, the Color Mapping options in the render settings are applied to the current render channel.
Consider for Anti-Aliasing – When enabled, anti-aliasing is used where possible.
Filtering – Applies the image filter to this channel. Image filter settings are in the Image Sampler tab of . Renderer node
Denoise – Enables the render element's denoising, provided the Denoiser render element is present.
Derive Raw Channels – Generates data in the raw channels by combining the respective color and the filter color channels.
VFB Color Corrections – Applies the post render color adjustments made from the VFB.
The table below provides a list of the channels that can be separated out with the Color Channel render pass.
|Atmosphere||Atmospheric effects, such as Environment Fog.|
|Background||Image background, such as any Background Texture specified in the Environment render settings.|
|Caustics||The caustics on the material. These caustics are present only when the Caustics option of V-Ray is enabled. This channel does not include GI caustics.|
|Pure diffuse surface color.|
|GI||The diffuse surface global illumination. Only present if Global illumination is enabled.|
|Direct Lighting||Diffuse direct surface lighting.|
|Material ID||Material ID of the object.|
|Matte Shadow||Matte shadow part of the image.|
|Noise Level||Outputs the noise level for pixels. Same as the noiseLevel render element produced by the VRayDenoiser, but as a standalone render element.|
|Raw Diffuse Filter||A solid mask of raw diffuse surface color information not affected by fresnel falloff.|
|Raw GI||Raw diffuse global illumination (not multiplied by the diffuse surface color). Only present if Global illumination is enabled.|
|Raw Direct Lighting||Raw diffuse direct illumination before it's multiplied by the diffuse surface color.|
|Raw Reflection||Pure surface reflection before it is multiplied by the reflection filter color.|
|Raw Reflection Filter||A solid mask of raw reflection information not affected by fresnel falloff.|
|Raw Refraction||Pure surface refraction before it is multiplied by the refraction filter color.|
|Raw Refraction Filter||A solid mask of raw refraction information not affected by fresnel falloff.|
|Raw Shadow||Raw light blocked by other objects.|
|Raw Total Lighting||Sum of all raw lighting, both direct and indirect.|
|Reflection||Reflections on the surface.|
|Reflection Alpha||Used by matte materials to store the alpha of the reflections.|
|Reflection Filter||Reflection filter (the color by which the raw reflections are multiplied to give the final surface reflection). This can be considered an alpha channel for reflections.|
|Reflection IOR||Stores floating-point information that corresponds to the Fresnel IOR values of scene objects' materials.|
|Refraction||Refractions of a surface.|
|Refraction Filter||The refraction filter mitigates the raw refraction layer. This render element returns the color by which the raw refractions are multiplied to give the final surface refraction. This can be considered an alpha channel for refractions.|
|Refraction Glossiness||Returns a float value that corresponds to the Refraction Glossiness value of an object's material.|
|Sample Rate||Shows an image where the pixel brightness is directly proportional to the number of samples taken at that pixel.|
|Self Illumination||Self-illumination of the surface.|
|Shadow||Diffuse light blocked by other objects.|
|Specular||Surface specular highlights.|
|SSS||Renders just the subsurface part of the V-Ray SSS material on a separate layer.|
|Total Lighting||Both direct and indirect lighting in the scene.|
|Unclamped Color||Shows the original colors that were clamped or adjusted with Color Mapping.|