HtoA 6.3.6.0

11 December 2024

HtoA 6.3.6.0 uses Arnold 7.3.6.0.

Installation

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

Various normal types for triplanar: The triplanar shader has a new parameter normal_type which can be used to select the type of normal to use for selecting the dominant axis for texturing. The options are shading, which is the previous behavior and uses the smooth shading normal (this normal includes bump), smooth_and_displaced is like the shading normal but without the bump, and finally smooth_before_displacing gives the smooth normal before displacement and bump. Note that smooth_before_displacing requires that autobump be enabled. (ARNOLD-15523)

shading	smooth and displaced

shading	smooth before displacing

Improve interoperability between Arnold and MaterialX shaders: It is now possible to connect Arnold closure shaders such as standard_surface and openpbr_surface to MaterialX surfaceshader shaders such as mix. (ARNOLD-15238)
Upgrade OCIO: OpenColorIO was upgraded to 2.4.0. (ARNOLD-15477)

shader_override in Hydra: Arnold scenes with shader_override set in the options can be exported to USD and rendered through Hydra now (usd#2119)
Operators in Hydra: Operators are now represented as UsdShade primitives. Arnold scenes with operators that are exported to USD can now be rendered through Hydra (usd#2110)
Updated Arnold schemas : Legacy Typed schemas were replaced with API schemas for the corresponding USD node types (usd#2088)
First support for versioned schemas: Versioned schemas (such as DomeLight_1) can now be rendered in USD and Hydra (usd#2145)

Additional metadata for parameter grouping and types: New metadata added for most base types (such as polymesh, shape, light, and skydome_light to specify information about parameters. (ARNOLD-15674)
- ui.groups - Information on the grouping of parameters, useful for applications to automate the display of parameters. This metadata was previously available for some shaders only. It is in the form of Group Name 1:param_1 param_2,Group Name2:param_3 param_4
- ui.hide - This boolean hides a parameter in an interface
- ray_vis_type - A boolean metadata for parameters that takes a byte value that represents a ray-type mask, for example, visibility, sidedness

AiMakeTx without color conversion: When AiMakeTx or maketx are run on a texture that has the same color space as the rendering space, a TX file with the suffix "raw" is created, following the same convention as what auto-tx does at render time. (ARNOLD-15636)
Correct narrow space with the OCIO env var: When the default color manager node is used with an environment variable OCIO pointing to a custom config file, Arnold now use a proper narrow space for 8-bit textures, instead of assuming a narrow space called sRGB. (ARNOLD-15634)

HTOA-2798 - Fixed Arnold Edit Material LOP error when a usdpreviewmaterial is present.
ARNOLD-12112 - Appending render causes buckets to be added in the wrong AOV
ARNOLD-15247 - Fixed crash on systems with vGPUs, or GPU in TCC mode under Windows
ARNOLD-15433 - OIDN treats AtVector as float2
ARNOLD-15488 - MaterialX published compound with promoted color port does not render correctly
ARNOLD-15533 - Fixed ordering of parameters in kick info
ARNOLD-15670 - Crash when modifying vlist on an instanced mesh
ARNOLD-15645 - Texture resolving not working with search path or path mapping in some cases
ARNOLD-15587 - Parameter reset on an instance node creates unnecessary array copies
ARNOLD-15278 - Crash on interactive modification of light_group or shadow_group array
ARNOLD-15668 - Resetting a procedural node should unload its children
usd#2129 - Fixed crashes when instancers have empty / invalid positions
usd#2131 - Wrong transform when an instanceable prim is not xformable
usd#2133 - Fixed crash when the root primitive is invalid
usd#2122 - RectLight doesn't take width / height into account with scenes exported from Arnold
usd#1764 - ArnoldUsd schema was missing from Arnold SDK
usd#2154 - Fix regression in Husk renders missing motion and velocity data

Houdini, Houdini FX, Houdini Indie and Houdini Education
- 19.5.805
- 20.0.896
- 20.5.410
- 20.5.445
Linux with at least glibc 2.28 and libstdc++ 9.3.1 (gcc 9.3.1) for Houdini 19.5, 20 and 20.5. This is equivalent to RHEL/CentOS 7.
Linux with at least glibc 2.17 and libstdc++ 11.2.1 (gcc 11.2.1) for Houdini 20/20.5. This is equivalent to Rocky 8.
macOS 11 or later
Apple Mac models with M series chips are natively supported by HtoA
x86-64 CPUs need to support the SSE4.1 instruction set. Apple Mac models with M series chip are supported natively mode.
GPU rendering works on Windows and Linux only and requires an NVIDIA GPU with the Maxwell architecture or later.
- On Linux, we recommend 535.104 or higher drivers.
- On Windows, we recommend 537.13 or higher drivers.
Optix™ denoiser requires an NVidia GPU with CUDA™ Compute Capability 5.0 and above.
Intel OIDN GPU support is limited to:
- MacOS
  - Apple native CPUs (M1 and newer)
- Windows
  - 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