Arnold for Maya (or MtoA) provides a bridge to the Arnold renderer from within the standard Maya interface.
Seamless integration with Maya shapes, cameras, lights and shaders.
Image Based Lighting support, including a state of the art physical sky.
Interactive rendering (IPR) allows parameter changes to be rapidly previewed without interrupting your work.
Support for volume rendering with Maya Fluids.
Support for Maya Hair and nHair.
Particles and nParticles support, including particle instancer.
Defer the creation of geometry at render time with the Stand-in placeholder nodes.
Productivity boost: override sets, holdout mattes, shadow catcher, passes, UDIM style textures, and arbitrary primvar data.
Extensible through plug-ins (Golaem, FumeFX for Maya, Yeti, Shave & Haircut).
Texturable geometric lights.
Rendering of curves.
Introduced new Arnold Material presets
Support for Color Management on Image Planes
Support IPR updates while using mesh Sculpting Tools
Support for curves width changes during IPR sessions
Fixed “region” argument in arnoldRenderView command
Fixed crash when renaming snapshots in Arnold RenderView (on OSX)
Support for MEL callbacks during IPR in Arnold RenderView
“Object” and “Barycentric” Debug Shading modes were inverted
Fixed the display of standins with VP2 for Maya 2016 Extension2
Changing image filename or color space updates the TX files during IPR (if auto-tx ON)
Fixed issue in TxManager using “files from folders” mode
Write maketx logs in windows and OSX
OpenVDB is now the default mode for volumes
Put the files from k into C:\solidangle\mtoadeploy\201x\bin