---
title: "Denoising"
canonical: "https://rmanwiki-25.pixar.com/space/RFH25/22642819/Denoising"
format: markdown
---
> ℹ️ See [Denoise Workflow](https://renderman.atlassian.net/wiki/spaces/REN20/pages/21561666) for more information.

  


![image](media://1593693b-258f-403c-a830-ad03a9a8c19b)

  


To output the multichannel EXR for the denoising workflow:

- ROP node > Images > Display Device >  OpenEXR (This is for exporting final renders, for previewing with the Nvidia AI Denoiser in "it" you can leave the Display Device as "it")
- Select Single Frame or Cross Frame in ROP's Images Tab.  This will auto-select the appropriate AOVs (only if you followed the step above)

  


![image](media://feef062b-28c9-4871-942e-bd812d6dfe2b)

![image](media://b2d9e783-cb66-453a-9fea-d2dd21e904e5)

  


> ❌ This setting is also required to the use the [Nvidia Denoise](https://renderman.atlassian.net/wiki/spaces/REN20/pages/21561593) preview in "it" as we set the filter type to Importance

  

  


- Create a new Denoise ROP node
- Connect the original RIS ROP node from the above steps to the Denoise ROP
- Be sure the Controls... are set to Node by Node

![image](media://bbe6bdf4-638a-4e37-b883-eed6410872c5)

  


![image](media://963c704c-caba-476c-af3f-b2fbcbc6e1fd)

  


You have two choices in the Denoise ROP node of importance:

- Denoise: This uses the Houdini process to render and denoise the EXR and will lock Houdini
- Denoise in Background: This creates a new process to render and denoise while leaving Houdini free

  


 *Keep in mind the **[Denoise](https://renderman.atlassian.net/wiki/spaces/REN20/pages/21561820)** feature requires a multi-channel EXR to work.*