---
title: "PxrAOVLight in Blender"
canonical: "https://rmanwiki-26.pixar.com/space/RFB26/321585174/PxrAOVLight%20in%20Blender"
format: markdown
---
![eyes_slide3.jpg](media://1eed996a-a5d0-443f-916c-ed0b9eba6361)

The [PxrAovLight](https://renderman.atlassian.net/wiki/spaces/REN26/pages/19661731) is a handy utility light that allows a lighting artist to output a shot-specific AOV mask without needing to request one from the shading artists. 

In this example, we'll break down a common request ... getting a refraction AOV for a character's eye  
(sclera or iris inside a cornea).

![RenderMan_AOVLight_1.JPG](media://4c43e74d-223f-4c93-b547-3289bc628d29)

![RenderMan_eyeball.jpg](media://5ee9f5a3-cc38-4457-bc1b-9f7c2ac06260)


### Creating the PxrAOVLight

The first thing we need to do is to create a PxrAovLight, which can be found in the RenderMan viewport panel under Add Light → PxrAovLight.

![RenderMan_AOVLight_2.jpg](media://5fd8dec6-9d87-4c19-9a9d-6ad24a6c4517)

Once created, we now need to set up the PxrAOVLight.

- Give your AOV a name, here we have used *irisMask*
- Set the “Use Color” attribute to on because we are writing to a color AOV.
- Since PxrAOVLight isn’t technically a light that illuminates the scene, we can turn off the “primary visibility” attribute.
- The “In Refraction” attribute is on because we need the rays to go through the cornea and hit the iris geometry.

![RenderMan_AOVLight_3.JPG](media://13265873-01dc-434c-851c-bed734355c51)


### Light Linking

Next, open the Light Linking tool, again, one place this can be found is in the RenderMan tool panel.

We use [light linking](https://renderman.atlassian.net/wiki/spaces/RFB26/pages/20086909) to include/exclude pieces of geometry in the AOV. 

In this example, the PxrAovLight is on for the Iris_GEO and off for the other parts of the eyeball.  
This linking setup creates a mask of the Iris inside the refractive cornea. 

![RenderMan_AOVLight_4.JPG](media://ba3068be-3c43-4bf2-8f30-7e6a149e8e1e)


### Defining the Output AOV

Once you have set an AOV Name in the PxrAOVLight attributes, use the [AOVs Manager](https://renderman.atlassian.net/wiki/spaces/RFB26/pages/20086935) to define a new display to which PxrAovLight will write the data to.

Note: Make sure the names match, like so:

|  |  |
| --- | --- |
| **PxrAOVLight** | *MyAOVName* |
| **Channel Source** | *MyAOVName* |

In this example, we used *irisMask *as the PxrAOVLight AOV name and the Channel Source name.  
  
Here, we’ve created a new display called **Iris**.  
Under **Iris**, we created a new channel called **irisMask** which must be the same AOV name we previously chose for our PxrAOVLight.

The AOVs Manager setup will look something like this:

![RenderMan_AOVLight_5.JPG](media://4eee096b-04db-44c4-bf54-ab216eb7976b)

And here’s the render of the irisMask AOV … Magic eh?!

![RenderMan_AOVLight_6.jpg](media://e52b3c51-44db-496b-8c49-a93b7fd3c119)


### Compositing

We can now use this mask inside compositing software to make further post-production adjustments. In Nuke, we have shuffled out the irisMask AOV into an alpha and used that as a mask input for a HueShift node to re-color the iris.

![RenderMan_AOVLight_7.JPG](media://64628b41-9118-4698-80b6-db77c1353d7e)