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Arnold for Maya 5.5.0 - Arnold for Maya

Arnold for Maya (MtoA) 5.5.0 uses Arnold 7.4.0.0 and is a minor feature release.

Installation

Enhancements

  • Improved MaterialX support: MaterialX has been upgraded to v1.38.10-OpenPBR, this new version brings support for the OpenPBR MaterialX node, improved Lama support and new nodes such as the NPR nodes. See v1.38.10, v1.38.9 release notes for details. (ARNOLD-15659)
  • Imager run once mode: Imagers can now be set to run only once, at the end of a bucket or the end of a completed final frame. This can be useful for particularly expensive imagers and can be enabled via the ImagerProperties::run_once property. (ARNOLD-12191)
  • Lights in procedural instances: Lights in instanced procedurals are copied for each instance. For example, instances of ASS or USD assets with lights now render the lights properly. (ARNOLD-15657)
  • Root primitive supported in MayaUSD exports : When you export with MayaUSD, if you set a root primitive then that is taken into account for Arnold nodes (such as lights). MTOA-2067
  • Arnold RenderView OpenColorIO updated to 2.4.1 : Arnold RenderView (ARV) now uses OpenColorIO version 2.4.1
  • Windows MSI to have the same naming conventions as other installers : The Windows MSI installer now has the same formatting as the other installers, including the operating system in the file name (MTOA-2261)
  • OpenColorIO 2.4.1: OpenColorIO has been updated to v2.4.1. (ARNOLD-15681)
  • Update Autodesk Desktop Licensing installer Arnold now uses Autodesk Desktop Licensing installer version 15.1, which includes the following components: AdskLicensingService 11.16.6.5912, AdskLicensingAgent 5.20.12.4281, and AdskLicensingInstHelper 2.13.1.2514.

USD Enhancements

  • Distant Lights normalize support : Distant lights now support the normalize attribute, so you can now disable normalize (before it was always enabled and the normalize attribute was ignored). You can use the Arnold option usd_legacy_distant_light_normalize to roll back to the previous behaviour. (usd#2176)
  • USD 24.11: The USD procedural now uses USD 24.11.

API Additions

  • Replace AtImagerSchedule with AtImagerProperties: The imager_prepare API has a new AtImagerProperties structure that provides more control over how an Imager should run. (ARNOLD-15774)

    Setting Imager bucket / full frame schedules will now work like so:

     imager_prepare
 {
    if (run_imager_full_frame)
       properties.schedule_full_frame = true;
    else
       properties.schedule_bucket = true;
 }

  • Improved return values for device selection API: AiDeviceSelect and AiDeviceAutoSelect now return the AtDeviceSelectErrorCode enum instead of an int to better describe the error status of the API call. (ARNOLD-14652)

    AtDeviceSelectErrorCode
    SUCCESS Device selection was successful
    FAILURE_NO_DEVICES_FOUND No Arnold compatible devices found
    FAILURE_NAME No matches found for options.gpu_default_names regular expression
    FAILURE_MEMORY No matching device has free memory greater than options.gpu_default_min_memory_MB threshold
    FAILURE_INVALID_ID Invalid device id in selection
    FAILURE_UNSUPPORTED Unsupported device in selection
    FAILURE_UNKNOWN Generic error

Incompatible Changes

This version of Arnold breaks binary compatibility. Shaders, procedurals, and other plugins compiled against older versions of Arnold are not compatible with this version of Arnold and must be updated and recompiled.

  • Autodesk Network Licensing version: Arnold 7.4 switches to ARNOL_2026 licensing. (ARNOLD-15400)

    • Single-user subscriptions will work with Arnold 7.4. The plugin installers automatically register the new version. If you do not use a plugin, then after you download Arnold, open the Arnold License Manager and click Register.
    • Existing network licenses will not work with Arnold 7.4. Log on to your Autodesk account to generate your new ARNOL_2026 licenses.
    • If you do not run the installers, and you manually register Arnold, then use--pk C0PR1 --pv 2026.0.0.F with the AdskLicensingInstHelper command.

  • Removed sss_use_autobump option: Use the per-object autobump_visibility flag. (ARNOLD-15782)

  • Removed legacy_volume_albedo: This option is no longer available as the new volume albedo is more useful. (ARNOLD-15782)

  • Removed AiMsgSetCallback(), AiMsgAddCallback(), AiMsgResetCallback(): Use AiMsgRegisterCallback() and AiMsgDeregisterCallback() instead. (ARNOLD-15782)

  • Removed AiASSLoad(), AiASSWrite(), AiASSWriteWithMetadata(): Use AiSceneLoad() and AiSceneWrite() instead. (ARNOLD-15782)

  • Removed deprecated versions of AiOrenNayarBSDF() and AiMicrofacetSetThinFilm(): Use the version with the same function name but additional arguments. (ARNOLD-15782)

  • Removed AiLoadImage(): Use AiReadImage() instead. (ARNOLD-15782)

  • Deprecated enable_new_quad_light_sampler and enable_new_point_light_sampler options: The new samplers should always be better, so these options are marked as deprecated and will be removed in a future version of Arnold. (ARNOLD-15782)

  • Distant Lights normalize support : Distant lights now support the normalize attribute, so you can now disable normalize (before it was always enabled and the normalize attribute was ignored). You can use the Arnold option usd_legacy_distant_light_normalize to roll back to the previous behaviour. (usd#2176)

  • The attribute aiHydra in the Arnold section of the mayaUSD proxy shapes was replaced with aiLegacyTranslation. Setting it to off triggers the hydra mode of the usd procedural (MTOA-2262)

  • Ass file exports are now always exported using the internal Maya internal units of centimeters. Units are now also correctly taken in to account when loading ass files created in other Arnold plugins into aiStandIn nodes.This can affect the look of some shader networks as they now will match the shading in scenes with different units. (MTOA-1892)

Bug Fixes

  • ARNOLD-15723 - No visible layering when layering a dielectric on top of a diffuse Lama shader, In MaterialX, layering of a Lama dielectric node on top of a Lama diffuse node was not generating the correct appearance of the diffuse surface coated with the dielectric. The OSL layering logic in Arnold has been improved to fix this issue.

USD Bug Fixes

  • usd#2201 - Hydra procedural should not modify the input usd stage with shutter range
  • usd#2197 - MaterialX textures not applied properly in hydra through mayaHydra

System Requirements

  • Maya 2024, 2025, or 2026
  • Windows 10 or later, with the Visual Studio 2019 redistributable.
  • Linux with at least glibc 2.17 and libstdc++ 4.8.5 (gcc 4.8.5). This is equivalent to RHEL/CentOS 7.
  • x86-64 CPUs need to support the SSE4.1 instruction set.
  • macOS 10.13 or later, macOS 11 and later for Maya 2024
  • Apple Mac models with M series chips:
    • Natively supported by Arnold for Maya 2024
    • Supported under Rosetta 2 mode for older versions of Maya
  • GPU rendering and Optix denoising work on Windows and Linux only, and require an NVIDIA GPU with the Maxwell architecture or later.
  • Intel OIDN GPU support is limited to:
    • Apple native CPUs (M1 and newer)
    • Intel Xe dedicated and integrated GPUs
    • NVIDIA GPUs using Turing or newer architectures
    • AMD GPUs with RDNA2 (Navi 21 only) and RDNA3 (Navi 3x) architectures
Parent page: MtoA 5.x

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