Enhancements
- HTOA-2320 - Added Inspect Arnold Operators option to the Arnold ROP menu
-Toon shader - improved detection of internal edges:The toon shader now does a better job of detecting angle threshold silhouettes that are internal to a single object. This is most apparent in the regions between nearly parallel surfaces of an object that are at different distances to the camera. (ARNOLD-10560)


-Improved mesh-lights sampling and update:Improved time to first pixel (up to 10% for scenes containing many large meshes) and overall render time (up to 5% for scenes with multiple flat mesh lights). (ARNOLD-13639)
-Improved interactive performance:Multiple optimizations to make interactive renders snappier by improving the interruption rate when modifying the scene. (ARNOLD-9833, ARNOLD-14077, ARNOLD-14083)
-Improved Global Light Sampling behavior around flat lights:Reduced noise with Global Light Sampling for surfaces near or behind flat lights (disk or quad lights). (ARNOLD-13192)


-Use dependency graph automatically for interactive renders:For interactive renders (IPR), the dependency graph is always enabled, regardless of the value of options.enable_dependency_graph. Interactive rendering updates for scene changes are improved by (and in some cases require) the dependency graph, so enforcing this setting avoids potential crashes. (ARNOLD-10732)
-Added support for alpha channel output in PNG driver:Added new boolean parameters skip_alpha and unpremult_alpha to the driver_png node. They behave in the same way as in the TIFF driver, with skip_alpha ignoring the alpha channel, and unpremult_alpha selecting either unassociated alpha (on) or associated alpha (off). Please note that PNG files with associated alpha are not supported by the PNG standard. (ARNOLD-10540)
-OpenColorIO Alias supportThe OCIO color manager now supports the use of OCIO color space aliases. (ARNOLD-13998)
USD Enhancements
-Custom MaterialX node definitionsMaterialX node definitions placed under a folder defined by the environment variable PXR_MTLX_STDLIB_SEARCH_PATHS are now supported when rendered with Arnold, through USD or Hydra usd#1632. There is no longer any restriction on the node definitions prefix and naming convention usd#1603.
-ArnoldProceduralCustom supportin Hydra Primitives ArnoldProceduralCustom are now supported inside of Hydra, and allow to render 3rd party Arnold procedural nodes usd#739.
API Additions
-AiMaterialxGetNodeEntryFromDefinition:Given a MaterialX node definition, returns the corresponding Arnold node entry. Arnold searches for node definitions in the materialx directory in the Arnold distribution and in any directory listed in the ARNOLD_MATERIALX_NODE_DEFINITIONS environment variable. The function returns the relevant Arnold node type if the node has a native Arnold implementation, or the OSL node type if the node has an OSL implementation only, so you can safely call AiMaterialxGetOslShaderCode with the same node definition. (ARNOLD-13957)
Incompatible Changes
-AiUniverseGetOptions() no longer returns "sanitized" threads count:AiUniverseGetOptions() returns the options set by the user, while AiRenderSessionGetOptions() returns the options actually used by the render. Previously this behavior was not followed for options.threads, and both the universe and render session's options contained a "sanitized" version of the thread count. For example, a thread count of 0 was interpreted as "autodetect" and sanitized to be the number of logical cores. Now, querying the universe options.threads can return 0 or other values that do not reflect what is being used. If the sanitized version is needed, replace AiUniverseGetOptions(universe) with AiRenderSessionGetOptions(AiUniverseGetRenderSession(universe)). (ARNOLD-14083)
Bug Fixes
HTOA-2312 - Fixed shader to USD material translation when nodes are grouped in a subnet
HTOA-1852 - Fixed wrong shader assignments with per-primitive shop_materialpath and alembic procedural
HTOA-2301 - Fixed IPR crash on macOS 11
ARNOLD-12005 - Hang when toggling denoiser ('N' key) in kick
ARNOLD-12205 - [GPU] Rare crash when process is terminating
ARNOLD-13709 - Invalid render when new OSL shaders are created interactively
ARNOLD-13823 - Correct scene scale conversion for nested procedurals
ARNOLD-13983 - Crash in IPR when enabling the OptiX denoiser, light mixer, or Arnold denoiser imagers
ARNOLD-13995 - Incorrect motion range in the instancer
ARNOLD-14065 - Artifacts with thick curves when scaling is applied
ARNOLD-14067 - Arnold MaterialX node definitions do not expose multiple outputs
ARNOLD-14074 - shidx not being gathered for alembic.material_attrbute string attribute
ARNOLD-14099 - Wrong separator used in the materialx paths
usd#1693 - Fix regression with Geometry lights in Hydra
usd#1696 - Fix regression with Cryptomatte in Hydra
usd#1613 - Invisible Hydra primitives should ignore arnold visibility
usd#1641 - Ensure nodes created by the render delegate have the correct parent procedural
usd#1673 - UsdUvTexture ignores missing textures in hydra
usd#1675 - Fix UsdUvTexture default wrap modes and uvset coordinates.
usd#1657 - Fix a motion blur sampling bug happening when a mesh has facevarying indexed normals and different number of indices per key frame
usd#1634 - Support curves orientations identically between USD and Hydra / Prevent errors due to bad curves orientations count
Arnold from Autodeskis an advanced unbiased Monte Carlo ray tracing renderer. It uses the power of your CPU to calculate illumination in the scenes by default. You can, however, switch between CPU and GPU rendering depending on your needs. Arnold is famous for its staggering hyperrealistic renders, which is why it's perfect for creating cinematic shots. When you have a massive amount of fine detail in your scene, when you're dealing with intricate textures, or when your lighting setup is complex, a precise renderer like Arnold will ensure that none of your hard work goes unnoticed. Think of the stunning visuals of Blade Runner 2049, Guardians of the Galaxy, or Tim Burton's Alice in Wonderland - all three were rendered using Arnold.
Arnold for Houdini (HtoA)provides a bridge to the Arnold renderer from within the standard Houdini interface. Having been in beta for several months, the plugin has already been used in production by many studios, including Prime Focus World for Hercules and Vampire Academy, Milk VFX for the Sherlock and Doctor Who TV series, and Framestore NY for the Captain Morgan commercials.
Houdini to Arnold Teaser
Teaser of the upcoming tutorials about Arnold for Houdini. I will be making a digital asset Arnold "uber" shader, showing how to make layered materials, explaining the general setting and at the very end texturing, rendering and multi-pass comping a Ferrari 458 Italia in NukeX. Available in 4k UltraHD
Solid Angleis leading provider of rendering software for animation and visual effects. The Arnold team believe that accurately and efficiently computing light transport in CG scenes is the best way to create stunning imagery for films and TV. Developers strive to provide clients with the best rendering tools to efficiently create realistic images. Solid Angle is a wholly owned subsidiary of Autodesk Inc, and has its offices in Madrid and London.
Autodeskhelps people imagine, design and create a better world. Everyone-from design professionals, engineers and architects to digital artists, students and hobbyists-uses Autodesk software to unlock their creativity and solve important challenges.