Arnold Rendering Configurations

This article is a memo about the Arnold rendering configurations that should be changed from the default, temporarily changed, and reverted after rendering.


Threads Configuration

You can change the number of threads to improve the viewport’s responsiveness while rendering with Arnold. The number of usable threads depends on your CPU. With modern CPUs, you can increase the thread count.

Change the Arnold RenderView Configuration

Follow the steps below to change the number of threads to two from the default value of one.

(1) Select the “Open Arnold RenderView” from the “Arnold” menu.

(2) Select “2” or “3” from the “Save UI Threads” sub-menu from the “Render” menu.

Change the number of the User interface threads in the Arnold RenderView window.
Modify the thread count for Arnold RenderView’s user interface.

Change the View Port Configuration

Follow the steps below to increment the number of threads for the viewport.

(1) Select “Arnold” from the “Render” menu in the viewport window.

(2) Select “2” or “3” from the “Save UI Threads” sub-menu from the “Render” menu in the Arnold ViewportRenderer Options window.

Change the number of UI threads for the viewport
Change the number of UI threads for the viewport

Arnold Renderview configuration will be saved

You might assume that the configuration gets saved, given the presence of “Save” in the menu item’s title. After relaunching, the configuration for the Arnold RenderView is restored but for the viewport. It was reverted to the default value of one. I checked it with Maya 2023. The future version of the Maya will resolve this issue.

Adaptive Rendering

“Adaptive Rendering” changes the Camera AA (Sampling) value adaptive. It reduces the rendering time while keeping rendering quality like a high AA value. The value could be higher than the original, so only sometimes turn on this function.

Follow the steps below.

(1) Turn on the “Enable” checkbox of the “Adaptive Sampling” in the “Arnold Renderer” tab in the “Render Settings” window.

(2) Enter the max Camera AA value into the “Max. Camera (AA)” and the min value into the “Camera AA” of the “Sampling”. For example, if you want to change Camera AA to 10 from 3, enter “10” to the “Max. Camera (AA)” and 3 to the “Camera AA”.

(3) Increment the value of the “Adaptive Threshold” slightly. It depends on the image, so you must adjust it with the rendering result. The default value is high quality, but the rendering time will be long.

Example of the rendering configurations
Example of the rendering configurations

Rendering Format

I prefer to use the “exr” format as the rendering format. It supports a high dynamic range.

The file size will be larger due to the significant amount of data it contains. There is a “Half Precision” option. It reduces the precision to half, and its data size will be smaller. The difference in image quality may not be perceptible to the naked eye. The “Half Precision” option is located in the “File Output” in the “Common” tab in the “Render Settings” window.

It will not be displayed until you set the image format to the “exr”.

Half Precision Option
Half Precision Option

Compare the result of Half Precision option

Compare the rendering result to see the effect of the “Half Precision” option. The image size is HD_1080 (1920×1080). The file size is below:

  • Half Precision Option Off: 4.06MB
  • Half Precision Option On: 1.51MB

The zip compression option is turned on. The file size was dramatically changed.

I opened these files with Photoshop and couldn’t find the difference with my eyes.

I calculated the difference between the two images using Photoshop, which reported that the pixels of both images were identical.

While this result may vary depending on the image, generally, there should be no issue even if the “Half Precision” option always remains on.

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Author of this article

Akira Hayashi (林 晃)のアバター Akira Hayashi (林 晃) Representative(代表), Software Engineer(ソフトウェアエンジニア)

アールケー開発代表。Appleプラットフォーム向けの開発を専門としているソフトウェアエンジニア。ソフトウェアの受託開発、技術書執筆、技術指導・セミナー講師。note, Medium, LinkedIn
Representative of RK Kaihatsu. Software Engineer Specializing in Development for the Apple Platform. Specializing in contract software development, technical writing, and serving as a tech workshop lecturer. note, Medium, LinkedIn