Arnold AO Light Filter

So, what is the Arnold AO Light filter and what does it do?

  • The Arnold Light filter overlays Ambient occlusion on all surfaces.
  • Makes it possible to get good spacial sense while rendering very fast in any interior-like situation.
  • If you combine it with Optix and switch to a RGBA ( denoised ) you get faster renders for dailies or even finals.

Check list:

  • Click here – to get the newest public build of Arnold installed on your system.
  • 3DS MAX 2018, 2019,2020,2021 running Arnold 6
  • Maya, Houdini, C4D supported as well running Arnold 6


3DS MAX 2018 – 2021, running Arnold 6 Download
Maya, any version running Arnold 6 Download
Houdini, any version running Arnold 6 Download
C4D, any version running Arnold 6 Download
Sample files archive for: 3DS MAX 2020, Maya, Houdini, C4d, Alembic Download



  • Download the light filter for 3ds max.
  • unzip the archive and drop the .dll file into c:\ProgramData\Autodesk\ApplicationPlugins\MaXtoA_*Your version*\ ( the image below shows MaXtoA_2020 )

  • Start 3DS MAX
  • Open the Material Editor and find the light filter under Arnold Maps in a category called AOLightFilter
  • Add an Arnold Skydome to the scene.
  • Turn Shadows OFF on the Skydome.
  • Add an Arnold Light filter on top of the skydome light.
  • Drag and drop the AOLightFilter to the Light filter slot.
  • Work with the AO Distance till it looks like what you want. ( Tip for interiors, set Far Clip to half the height of the room to favor speed and looks )


  • in maya the best way is to create a folder(LightFilter) with 2 subfolders(ae & bin)
  • AOLightFilter.dll & AOLightFilter.mtd in bin folder
  • in ae folder
  • ARNOLD_PLUGIN_PATH = C:\LightFilter\bin
  • MTOA_TEMPLATES_PATH = C:\LightFilter\ae


  • in Houdini create a folder (LightFilter) with 2 subfolders(ae & bin)
  • AOLightFilter.dll & AOLightFilter.mtd in bin folder
  • in ae folder
  • Then add ARNOLD_PLUGIN_PATH variable
  • ARNOLD_PLUGIN_PATH = C:\LightFilter\bin
  • ARNOLD_PLUGIN_PATH in houdin.env file or a json.fil


  • Put: AOLightFilter.dll & AOLightFilter.mtd in: C:\Program Files\Maxon Cinema 4D R21\plugins\C4DtoA\arnold\plugins
  • You can access the plugin via Arnold Shader Network Editor in Light filter section
  • If you want to get ambient_occlusion_lightfilter showing in create menu (Create->arnold->Light Filter)
  • You have to override c4d_symbols.h with provided one
  • Overrides in C:\Program Files\Maxon Cinema 4D R21\plugins\C4DtoA\res
  • Put arnold light_filter.str in : C:\Program Files\Maxon Cinema 4D R21\plugins\C4DtoA\res\strings_en-US\description
  • Put ainode_light_filter.res in : C:\Program Files\Maxon Cinema 4D R21\plugins\C4DtoA\res\description

Technical and general info:

  • The Arnold AO Light Filter was originally fabricated by Mike Farnsworth from Autodesk/Solid based on an idea by Aaron on the Arnold Mail ring.
  • Screenshotsm .py and .MTD for Maya, Houdini & C4D provided by rachid Hadj Abderrahmane
  • I am maintaining the c++ project files and recompile it against new SDK’s in the future.