5.4.8 - Arnold for Maya

13 February 2025

MtoA 5.4.8 uses Arnold 7.3.7.0 and is a minor feature release.

Installation

Download Arnold for Maya from your Autodesk Account. See Download Arnold for more information about downloading MtoA from your Autodesk Account.
Follow these installation instructions.

Enhancements

Improved, more realistic shadows for glass objects: Transparent objects like clear glass now cast shadows. The look of the shadow is controlled by the new transmission_shadow_density parameter on the openpbr_surface and the standard_surface shaders. (ARNOLD-6881, ARNOLD-15863, ARNOLD-15828)


0	0.5	0.9	1

	transmission shadow density = 0	transmission shadow density = 1
caustics off
caustics on

Improved Global Light Sampling (GLS) on glossy materials: GLS now takes material glossiness into account when sampling, which greatly enhances the quality especially when many small lights are present. It causes small slowdowns for fixed AA renders, but for adaptive renders, it brings overall speedups. For example, with adaptive in the robot scene below we achieved 1.7x speedup. This feature can be enabled and disabled using GLS_glossy_enable. (ARNOLD-15489)


7.3.5, fixed AA	7.3.7, fixed AA

_{Camera(AA): 2, Specular: 1.}

- Create multiple mesh lights from multiple selected meshes : The Create Mesh Light menu command now create a mesh light for each selected mesh (MTOA-2204)
Add logs for Render To Texture : A new option -log has been added to the arnoldRenderToTexturecommand and to the UI, to allow users to produce a render log for debugging issues (MTOA-2181)
Arnold Render View - Log Viewer : Add tabs for viewing saved logs and loading log files : Tabs have been added to the Log Viewer to allow you to copy from the live log and load log files from disk (ARNOLD-15640)
New Arnold RenderView Icons : Arnold RenderView has had new improved DPI-aware icons (ARNOLD-14264)
New OpenPBR icons : New icons have been added for the aiOpenPBRSurface in the Hypershade, and the Arnold openpbr_surface shader in LookdevX (MTOA-2215)
Match alembic motion keys to the scene : aiStandin nodes have a new abcUseSceneMotionKeys parameter that sets the number of motion keys for an alembic procedural to the same as the current scene (MTOA-2226)
Optimize handling of interactive object visibility changes: Improved detection of visibility changes gives faster scene updates. (ARNOLD-15708)
Update Autodesk Analytics Program: A newer version of the Autodesk Analytics Program (ADP) has been integrated into Arnold. This brings performance and stability improvements. In particular, instead of waiting for five minutes, ADPClientService.exe now quits as soon as Arnold terminates and ADPClientService finishes its processing. (ARNOLD-15396, ARNOLD-12865)
Update CER: The Customer Error Reporting (CER) library is updated to v7.1.3. (ARNOLD-13834)
Update OpenImageIO: OpenImageIO has been updated to v2.6.3.0. (ARNOLD-13742)

USD Enhancements

Arnold parameters in USD nodes are now undoable - Changes to Arnold byte-type attributes such as visibility, sidedness, and subdiv_iterations, in MayaUSD schemas are now undaoable (MTOA-2193)
Better Hydra support: Improved compatibility with recent USD versions and Solaris:
- Handle the DirtyRender tag properly in Hydra. usd#2170
- Use Stop render instead of Pause render in Hydra, to avoid restarting renders when the user views a difference render output (AOV). usd#2177
Add more render statistics: The time taken to read the stage is not included in the Arnold render stats. usd#2190

API Additions

Nice name metadata for nodes and parameters - New metadata has been added for setting how a node or parameter name should appear in a UI called ui.name, currently used for openpbr_surface to be named *"OpenPBR Surface"* in LookdevX and MaterialX node definitions. (ARNOLD-15690)
Shared Arrays - The new API function AiArrayMakeShared allows you to share a buffer with Arnold instead of copying it to an allocated Arnold AtArray. The owning application cannot modify or delete a shared buffer. Arnold calls the provided callback function passed to AiArrayMakeShared when Arnold is no longer using the buffer. Here is an example that shows a local buffer containing cube points shared with Arnold.

   const AtVector vlist[8] = {{-0.25, -0.25, -0.25}, {0.25, -0.25, -0.25},
                              {0.25, -0.25, 0.25},   {-0.25, -0.25, 0.25},
                              {-0.25, 0.25, -0.25},  {0.25, 0.25, -0.25},
                              {0.25, 0.25, 0.25},    {-0.25, 0.25, 0.25}};
   AiNodeSetArray(polymesh, USTR::vlist,
                  AiArrayMakeShared(8, AI_TYPE_VECTOR, &vlist[0]));

Bug Fixes

MTOA-2106 - Converting aiStandardSurface or standardSurface to aiOpenPBR via Arnold menu did not remove the original shader
MTOA-1929 - Arnold Render View switches from USD camera on full update or changing to or from GPU
MTOA-2194 - Viewport renders not starting when using UFE cameras
ARNOLD-7549 - PNG textures with partial alpha render too dark
ARNOLD-15704 - Long UFE camera paths creating very long ARV camera selector menu bar.
ARNOLD-15543 - Gamma icon in Render View doesn't scale with DPI
ARNOLD-15082 - Isolate select icon is covering information in the ARV status bar
ARNOLD-15556 - clip_geo not fully working with instances of procedurals
ARNOLD-15828 - [GPU] Shadow artifacts with transmission or opacity
ARNOLD-15901 - Random crash when updating instancers
usd#2159 - User data errors with deformed meshes and subdivision
usd#2168 - Updated code calling SamplePrimvar following the changes in USD 24.08 affecting motion blur.
usd#2187 - Cannot override output image with Arnold product types

System Requirements

Maya 2023, 2024, or 2025
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.
- On Linux, we recommend 560.35.03 or higher drivers.
- On Windows, we recommend 560.76 or higher drivers.
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