This page provides information on the Cryptomatte Render Element in V-Ray for Unreal.
Overview
Cryptomatte is a method developed by Psyop for efficiently encoding accurate mattes. It typically uses three to five automatically generated render channels stored in a multichannel OpenEXR file which removes the hassle of creating dozens or hundreds of Multimattes. Using the Cryptomatte plugin for NUKE or Fusion, mattes can be extracted through directly picking objects or entering object names.
In order for Cryptomatte to properly work Interactive, Enable Viewport Rendering have to be disabled and Use Bucket Rendering has to be enabled in V-Ray Settings.
Cryptomatte
Enable – Enables the rendering of the channels included in this render elements group.
– Adds additional render elements to the render elements group.
– Deletes all the render elements in the render elements group.
Active – Enables the render of the current channel.
Denoise – Enables the render element's denoising, provided the Denoiser render element is present.
Consider for AA – By default, the Image sampler applies AA based on the RGB image. When this option is enabled, the Render Element is considered for AA.
Filtering – When enabled, it applies the antialiasing filter to the render element.
Color Mapping – Applies the default color mapping options to this render element (Reinhard).
Id Type – Specifies how the ID mattes are determined.
Node name – Creates mattes by Actor names.
Node material name – Creates mattes based on the materials in the scene.
Currently due to limitations materials are separated based on Shading Model: Unlit, Default Lit, Subsurface, ClearCoat, TwoSidedFoliage.
Node name with hierarchy – Creates mattes by node names and takes the node hierarchy into account for linked or grouped objects.
Sub object name – Creates separate mattes for each individual object within a V-Ray Proxy, when the proxy file contains more than one objects. This option works by getting IDs from within the vrayProxy node by creating a mask for each sub-object of the proxy ( .vrmesh). This type produces masks for V-Ray Proxy objects only - regular geometry is not included in this cryptomatte layer.
Num Levels – Specifies the number of levels for the render element, which determines the number of objects that can be distinguished per pixel. If multiple objects intersect at a single pixel, higher-order elements will contain non-zero results. The default value of 6 is normally enough for most cases.
