Standard AOVs

Eddy has a large number of built-in AOVs, for both different light paths and utility outputs.

In addition to the built-in AOVs, custom AOVs can be created using Light path expressions and can have custom output modes and clamping settings.

Note

All standard AOVs support a light tag filter, which will restrict the AOV to include only radiance from the tagged lights. Creating a custom AOV is only required if specialized light paths are required, more complicated conditions are required to select the lights, or to change the output modes.

Standard light path AOVs

These AOVs select light based on the path taken by the light from the light source to the camera.

beauty The ‘beauty’ AOV is the default output in Eddy. It is actually identical to the ‘beauty_without_caustics’ AOV, as caustics are excluded by default because they can have a high level of noise in a non-bidirectional renderer like Eddy.

beauty_with_caustics Includes all light paths, including caustics which are usually excluded from the regular ‘beauty’ AOV. Equivalent light path expression: C.*

beauty_without_caustics All light paths except caustics. Equivalent light path expression: C([SG]*|(.*<[RTV][^SG]>[^SG]*))[LO]

direct Direct lighting from light sources only, i.e. a single bounce. Equivalent light path expression: C[RTV]L

indirect Indirect lighting only, i.e. secondary light bounces. Equivalent light path expression: C[RTV][RTVOB].*

emission Emissive sources only. Equivalent light path expression: C[LO]

background Background, i.e. color from rays that don’t hit any object. Not currently used by Eddy. Equivalent light path expression: CB

reflection Light from surface reflections. Note this includes diffuse, glossy, and specular reflections. Use the ‘specular’ AOV if only specular reflections are wanted. Equivalent light path expression: C<R.>.*

transmission Light from surface transmission. This include specular refraction as well as sub-surface scattering. Equivalent light path expression: C<T.>.*

diffuse Light from diffuse reflection from surfaces. Equivalent light path expression: C<RD>.*

specular Light from specular reflection from surfaces. Equivalent light path expression: C<RS>.*

glossy Light from glossy reflection from surfaces. Equivalent light path expression: C<RG>.*

refraction Light from surface refraction. Equivalent light path expression: C<TS>.*

subsurface Light from subsurface transmission. Equivalent light path expression: C<T[DG]>.*

volume Light from volumes. Equivalent light path expression: CV.*

caustics Light from caustics, i.e. light that has one or more specular bounces before hitting a diffuse surface. Equivalent light path expression: CD[SG]+[LO]

caustics_all Light from caustics and caustic secondary bounces. These are the caustics that are removed from the ‘beauty_without_caustics’ AOV. The secondary caustics would not usually be classified as traditional caustics, but are still a source of noise. Equivalent light path expression: C.*<[RTV][^SG]>[SG]+[LO]

Combination light path AOVs

These AOVs are various combinations of the standard light path AOVs.

direct_reflection Direct lighting from surface reflections. Note this includes diffuse, glossy, and specular reflections. Use the ‘direct_specular’ AOV if only specular reflections are wanted. Equivalent light path expression: C<R.>L

direct_transmission Direct lighting from surface transmission. This include specular refraction as well as sub-surface scattering. Equivalent light path expression: C<T.>L

direct_diffuse Direct lighting from diffuse reflection from surfaces. Equivalent light path expression: C<RD>L

direct_specular Direct lighting from specular reflection from surfaces. Equivalent light path expression: C<RS>L

direct_glossy Direct lighting from glossy reflection from surfaces. Equivalent light path expression: C<RG>L

direct_refraction Direct lighting from surface refraction. Equivalent light path expression: C<TS>L

direct_subsurface Direct lighting from sub-surface transmission. Equivalent light path expression: C<T[DG]>L

direct_volume Direct lighting from volumes. Equivalent light path expression: CVL

indirect_reflection Indirect lighting from surface reflections. Note this includes diffuse, glossy, and specular reflections. Use the ‘direct_specular’ AOV if only specular reflections are wanted. Equivalent light path expression: C<R.>[RTVOB].*

indirect_transmission Indirect lighting from surface transmission. This include specular refraction as well as sub-surface scattering. Equivalent light path expression: C<T.>[RTVOB].*

indirect_diffuse Indirect lighting from diffuse reflection from surfaces. Equivalent light path expression: C<RD>[RTVOB].*

indirect_specular Indirect lighting from specular reflection from surfaces. Equivalent light path expression: C<RS>[RTVOB].*

indirect_glossy Indirect lighting from glossy reflection from surfaces. Equivalent light path expression: C<RG>[RTVOB].*

indirect_refraction Indirect lighting from surface refraction. Equivalent light path expression: C<TS>[RTVOB].*

indirect_subsurface Indirect lighting from sub-surface transmission. Equivalent light path expression: C<T[DG]>[RTVOB].*

indirect_volume Indirect lighting from volumes. Equivalent light path expression: CV[RTVOB].*

Collector AOVs

These AOVs include only objects with the tag ‘collector’ and are used to collect shadows and reflections. See Shadow and reflection collecting for more details.

collector_shadows Shadows on the collector objects. The shadow value is scaled from 0 to 1, where 0 is no shadow and 1 is full shadow. Equivalent light path expression: C<RD ‘collector’>.*

collector_direct_shadows Shadows on the collector objects from direct lighting only. The shadow value is scaled from 0 to 1, where 0 is no shadow and 1 is full shadow. Equivalent light path expression: C<RD ‘collector’>L

collector_shadow_difference Shadows on the collector objects. The shadow value is the difference in color between the shadowed and unshadowed values, i.e. the color that the shadow has subtracted. Equivalent light path expression: C<RD ‘collector’>.*

collector_direct_shadow_difference Shadows on the collector objects from direct lighting only. The shadow value is the difference in color between the shadowed and unshadowed values, i.e. the color that the shadow has subtracted. Equivalent light path expression: C<RD ‘collector’>L

collector_reflections Reflections on the collector objects. Equivalent light path expression: C<R[SG] ‘collector’>[RTV].*

collectors The collector objects themselves. This AOV can be useful for debugging collectors, as usually they will also be holdouts and won’t appear in the normal ‘beauty’ AOV. Equivalent light path expression: C<.. ‘collector’>.*

Albedo AOVs

The albedo AOVs return the color of the objects without lighting.

albedo The albedo of all objects. Equivalent light path expression: C[RTV]A

albedo_reflection The reflective albedo. Includes diffuse, specular, and glossy reflections. Equivalent light path expression: C<R.>A

albedo_transmission The transmissive albedo. Includes both refraction and sub-surface transmission. Equivalent light path expression: C<T.>A

albedo_diffuse The diffuse reflective albedo. Equivalent light path expression: C<RD>A

albedo_specular The specular reflective albedo. Equivalent light path expression: C<RS>A

albedo_glossy The glossy reflective albedo. Equivalent light path expression: C<RG>A

albedo_refraction The refraction albedo. Equivalent light path expression: C<TS>A

albedo_subsurface The sub-surface albedo. Equivalent light path expression: C<T[DG]>A

albedo_volume The volume albedo. Equivalent light path expression: CVA

Utility AOVs

These AOVs return various utility values.

The source render used for all the velocity and motion AOV example images.

position The world space position (colors in the example image have been re-scaled).

position_camera The camera space position.

velocity The world space velocity (colors in the example image have been re-scaled). By default the velocity of the closest hit point is returned, alternatively the AOV output mode can be changed to ‘alpha weighted’ to blend the velocity from volumes.

velocity_camera The world space velocity. By default the velocity of the closest hit point is returned, alternatively the AOV output mode can be changed to ‘alpha weighted’ to blend the velocity from volumes.

normal The shading normal of the hit surface (colors in the example image have been re-scaled).

geometric_normal The geometric normal of the hit surface (colors in the example image have been re-scaled).

depth The depth of the hit point (colors in the example image have been re-scaled).

uv The UV coordinates of the surface hit point.

motion The screen space motion vector of the hit point. By default the motion of volumes are blended using the ‘alpha weighted’ mode, however the AOV output mode can be changed to ‘closest’ if only the motion of the closest point is desired. The render settings control whether this AOV will store the forward, backward, or instantaneous motion vectors. The AOVs ‘motion_forward’ and ‘motion_backward’ can be used to explicitly request a particular type (or to output multiple motion vector types from a single render). If a maximum motion value is specified in the render settings, then these values will be re-scaled from 0 to 1, where 0.5 corresponds to no motion.

motion_forward The screen space forward motion vector of the hit point, i.e the vector from the current point to its position in the next frame. By default the motion of volumes are blended using the ‘alpha weighted’ mode, however the AOV output mode can be changed to ‘closest’ if only the motion of the closest point is desired. If a maximum motion value is specified in the render settings, then these values will be re-scaled from 0 to 1, where 0.5 corresponds to no motion.

motion_backward The screen space backward motion vector of the hit point, i.e the vector from the current point to its position in the previous frame. By default the motion of volumes are blended using the ‘alpha weighted’ mode, however the AOV output mode can be changed to ‘closest’ if only the motion of the closest point is desired. If a maximum motion value is specified in the render settings, then these values will be re-scaled from 0 to 1, where 0.5 corresponds to no motion.

id The ID of the hit object.

opacity The opacity of the pixel, i.e the colored version of the pixel alpha. Volumes with colored extinction will also have colored opacity.

sample_count The number of camera samples taken for each pixel (colors in the example image have been re-scaled). When adaptive sampling is used some pixels will need less samples to reach the required error threshold.

ray_count The number of rays traced for each pixel (colors in the example image have been re-scaled).