HtoA is a bug fix release using Arnold, fixing an issue with operator traversal and the camera projection shader parameters.  It features Arnold-USD (4e5710fa).


  1. Download Arnold for Houdini

  2. Follow these installation instructions

    New Windows system requirement

    If you use the Extract contents only option to install HtoA, you must manually install the Microsoft Visual C++ 2015-2019 Redistributable.

    The VCRedist install is in the HtoA redist folder. For example:


Autodesk Network Licensing in Arnold 6 requires new license files with an updated 2020 version. Please follow the instructions on this page to generate your license file. More info about Arnold 6 licensing can be found here.


System Requirements

  • Houdini, Houdini FX, Houdini Indie and Houdini Education
    • 17.5.460
    • 18.0.597
    • 18.5.351
    • 18.5.408
  • Windows 7 or later, with the Visual Studio 2019 redistributable.
  • Linux with at least glibc 2.12 and libstdc++ 3.4.13 (gcc 4.4.7). This is equivalent to RHEL/CentOS 6.
  • OSX 10.11 to 10.15. Note that macOS 11 Big Sur is not certified.
  • CPUs need to support the SSE4.1 instruction set.
  • GPU rendering works on Windows and Linux only and requires an NVIDIA GPU of the Turing, Volta, Pascal, or Maxwell architecture. We recommend using the 455.38 or higher drivers on Linux and 457.09 (Quadro), 457.30 (GeForce), or higher on Windows. See Getting Started with Arnold GPU for more information.
  • Optix™ denoiser requires an NVidia GPU with CUDA™ Compute Capability 5.0 and above.

Bug Fixes

  • htoa#1581 Fix operator traversal for subnets created via a script
  • htoa#1583 Restore the camera_projection shader's camera parameter

  • htoa#1585 Correct the indirect_specular_blur type from int to float, now located in the Advanced group


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