MtoA is a plug-in for Autodesk Maya which provides a bridge to the Arnold rendering system from within the standard Maya interface.

Enhancements
Faster polymesh node init: Time needed for polymesh node initialization has been reduced when there are many meshes being initialized at the same time on machines with many CPU cores. For instance, the Activision Caldera scene went from 63s to initialize to 8.7s on a 120-core Windows machine. (ARNOLD-16008)

Parallel instancer initialization: Multiple instancer nodes can now initialize at the same time. On a 120-core Windows machine the scene init time for the Intel Jungle USD scene went from 115s to 43s. (ARNOLD-16120)

Minor Imager performance improvement: Enhanced memory copy operations within the Imager framework, resulting in improved performance. Stress tests demonstrate a reduction of 60 milliseconds per Imager chain. (ARNOLD-16256)

parallel_init metadata: A warning is now printed when the parallel_init metadata is missing from a procedural. Missing metdata results in parallel_init being disabled for the procedural, which can result in slower scene initialization for those procedurals that could have safely benefited from parallel initialization. (ARNOLD-7051)

Update Autodesk Desktop Licensing: Autodesk Desktop Licensing is updated to v15.3.0.1298. See the release notes for more information on this release. (ARNOLD-16104)

Upgrade OIIO components: Various components used by OpenImageIO have been upgraded to more recent versions. In particular, jpeg files should now load and write noticeably faster than before. (ARNOLD-7892, ARNOLD-15771)

Upgrade Customer Error Reporting (CER): CER was upgraded to 7.1.8 to address security vulnerabilities. (ARNOLD-16144)

Upgrade Autodesk Analytics Program: Arnold includes a newer version of the Autodesk Analytics Program (ADP), which brings stability and performance improvements. (ARNOLD-16031)

Bug Fixes
MTOA-2228 – Render Settings > AOV browser is blank on macos
MTOA-2348 – Render settings: render unit parameter not working
usd#2298 – Fix a potential crash when multiple Hydra renders initialize concurrently.
usd#2300 – Animated sequences render an incorrect filename in Hydra mode
usd#2260 – Deepexr settings were not set properly with husk renders
usd#2231 – Fix velocity motion blur coherence when there is varying number of instances
usd#2287 – Fix mismatch in default value for GI_transmission_depth between USD and Hydra

System Requirements
Maya 2023, 2024, 2025 and 2026
Windows 10 or later, with the Visual Studio 2019 redistributable.