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Intro to AOVs

Table Of Contents


Introduction

AOV Type: Integrated AOV

AOV Output: Reflection AOV

Integrated Utility AOV

Depth AOV

Custom AOV

Custom wireframe







Beauty


AOV stands for "arbitrary output variables". It refers to the different types of per-pixel information Redshift can produce. While typically Redshift will only produce a color for each pixel of the frame you can configure it to include individual shading elements like reflections, refractions, global illumination, etc. Redshift can output these shading elements isolated on their own separate AOV pass which can help with things like fast small-scale color adjustments in post without having to re-render the entire frame. These built-in AOVs are referred to as Integrated AOVs. You can add even more control with Integrated AOVs by making use of Light Group AOVs, these can give you per-light control of your render in post.

There are other built-in AOVs that can contain non-beauty data like depth information, motion vectors, and world position information. These kinds of AOVs can be used in post to allow for much greater flexibility, like being able to add bokeh depth of field effects by making use of a Depth AOV. These types of built-in non-beauty AOVs are referred to as Utility AOVs.

There may also be times where you need to output custom data that isn't covered by an integrated AOV or wouldn't be output as a shading element of the beauty rendering process. In situations like this you can turn to Custom AOVs, these allow you to define your own custom render output for specific needs you may have like a custom ambient occlusion pass. Normally you might accomplish something like this as a completely separate render and pay the price in additional render time, but this can be avoided by using Custom AOVs instead since they are processed and output at the same time as your primary beauty render.

This page covers the basics of creating and managing AOVs for Redshift as well as the most common options available for AOV output. 


Managing AOVs


Per-AOV General Options

This section covers the common per-AOV parameters that are available for most AOVs.


AOV

This section shows you what type of AOV it is.


Name

Here you can set your own custom name for the AOV, by default this is set to the type of AOV.


File Name Prefix / Path

This section shows you how the AOV file names will be output and allows you to change that here.


Data Type

Select the data output type for the AOVs from the following options:

By default AOVs output as RGB image files with no alpha.


Format

Select the image file format from the following options:

By default Redshift AOVs use OpenEXR file format.


Bits Per Channel

Select the bits per channel:

By default Redshift AOVs use Half float (16 bits).


Bits per channel options are dependent on the AOV file format currently selected.


Compression

Select the compression method for the relevent file format:


DWA Compression Level

Set the level of compression for OpenEXR file format, default of 45 will yield a perceptibly lossless image but a drastic reduction in file size. Higher values mean more compression at smaller file sizes and vice versa. 


This setting only affects the DWAA and DWAB OpenEXR compression methods.


Storage Format

Select the storage format:

By default Redshift AOVs use scanline.


Apply Color Processing

Enables or disables "Apply Color Processing."

The "apply color processing" option means that gamma correction (if gamma is other than 1.0) and photographic exposure (if a photographic exposure lens shader is present) will both be applied to the AOVs.

Several AOVs have an "apply color processing" option which is enabled by default. These AOVs are:


AOV Processing


This section controls the way all other AOVs are processed and is found under the AOV render settings tab.


Enable Deep Output

Enables or disables OpenEXR deep output.


For more information on Deep output for Redshift please see this page where all of the deep settings below are covered in much greater detail.


Deep Merge Mode

Select the Deep merge mode:


For the ObjectID Deep Merge mode to be effective, objects need to be assigned different ObjectIDs.


Deep Merge Z Threshold

The "Deep Merge Z Threshold" parameter controls how close the samples will need to be in order for them to be merged together.


This setting only applies to Deep Merge Mode: Z


Enable Clamping (Color and AO channels only)

This enables clamping on AOVs separate from the beauty.

In Redshift's Output tab and in Redshift's AOV tab there are options to clamp the color/AO AOVs. Redshift can perform sub-sample intensity clamping during unified sampling, which limits noise (grain) that can be produced when combining depth of field and motion blur with bright light sources. The AOV clamping offers the same type of sub-sample control for AOVs. Please refer to the  AOV tutorial page for more information about how and when these should be used.


Max Value

This sets the maximum sub-sample intensity clamping value for AOVs.


Disable Importance-based Optimizations

Redshift has importance-based optimizations that can result in samples being dropped if they are deemed too dim to impact the final appearance of the beauty render, which is great for performance. AOVs however can suffer from these kind of optimizations, because if you wanted to brighten your reflections AOV channel and samples had been dropped because they were deemed too dim, then you would reveal unexpected noise that would be difficult to clean up by hand.


Disabling Importance-based Optimizations will not add noise to the beauty, but it will impact rendering performance.

By default Redshift uses importance-based optimizations for all AOVs.


Adjust RAW AOVs To Fix Halo Artifacts

This option works by adjusting the Raw AOV results based on the appropriate Filter AOV results in order to ensure the resultant composite will match the beauty. Because of this adjustment, you may see unexpected colors around the high-contrast edge images in the Raw AOVs – while this may look strange, mathematically it ensures the correct beauty results when multiplied with the appropriate albedo Filter AOV. For more information, please see  here.

By default this option is enabled to ensure final composites matches beauty.