KtoA 4.3.4.0 now available

[Stephen.Blair]

29 August 2024

KtoA 4.3.4.0 uses Arnold 7.3.4.0 and is a feature release.

Installation

• Download the Arnold for Katana plugin
• Follow these installation instructions

Katana 4.5 and 5.0 compatibility

Katana 4.5v3 and 5.0v3 introduced a change that affects the Arnold USD plugins support in Katana. This release of KtoA supports those Katana versions or newer within their release series. Katana 4.5v1, 4.5v2, 5.0v1, and 5.0v2 are not supported by this KtoA release.

Enhancements

• OpenPBR improvements
  • View-dependent coat absorption: The coat lobe now more accurately models the absorption tinting at grazing angles, producing a slightly more realistic look. (ARNOLD-15377)

	Smooth Coat	Rough Coat
7.3.3.0
7.3.4.0

• SSS color matching: The SSS model has been tuned to ensure that the color of dense SSS more closely matches the supplied subsurface_color, as required by the OpenPBR specification. (ARNOLD-15328)

	- top row: diffuse with a given base_color - middle row: Standard Surface (dense) SSS, with same color assigned to subsurface_color - bottom row: OpenPBR (dense) SSS, with same color assigned to subsurface_color
7.3.3.0
7.3.4.0

• Scaling of emission luminance from nits to Arnold units: nits_per_unit was added to the options node, and OpenPBR Surface's emission_luminance (in nits) is internally scaled down by this nits_per_unit value (defaulting to 1000) to bring it into Arnold units. This ensures that the default soft-maximum of emission_luminance of 1000 nits corresponds to the former behavior of Standard Surface at emission 1. (ARNOLD-15364)

• Faster startup times on GPU: We have made several optimizations to improve startup and scene update time on GPU. These improvements will be most noticeable on scenes with many objects. Startup times on Windows are also now on par with startup times on Linux. On a scene with 1 million instances, we see the following improvements when compared to the previous release. (ARNOLD-15271, ARNOLD-15279, ARNOLD-15310)

  	7.3.3.1	7.3.4.0	Improvement
  GPU update time (Windows)	204s	17s	12X
  GPU update time (Linux)	37s	18s	2X

• Faster texture opacity lookups in OSL shaders: OSL shaders used in opacity inputs (for example OpenPBR Surface's geometry opacity) now read opacity mask textures faster and with smaller memory footprint. (ARNOLD-15340)

• Improved node and parameter introspection with kick

  • kick -info <node> now groups node parameters by their UI Group metadata, or by whether the parameters are Input or Output. (ARNOLD-14198)

    For example, here's the first few UI groups of openpbr_surface:

    $ kick -info openpbr_surface
    node:             openpbr_surface
    type:             shader
    implicit output:  CLOSURE
    parameters:       65
    multioutputs:     0
    filename:         <built-in>
    version:          7.3.4.0
    
    Type          Name                      Unlinkable  Default        Bounds
    ------------  ------------------------------------  -------------  ---------
    Base
     FLOAT        base_weight                           1              [0, 1]
     RGB          base_color                            0.8, 0.8, 0.8
     FLOAT        base_diffuse_roughness                0              [0, 1]
     FLOAT        base_metalness                        0              [0, 1]
    Specular
     FLOAT        specular_weight                       1              [0, +inf]
     RGB          specular_color                        1, 1, 1
     FLOAT        specular_roughness                    0.3            [0, 1]
     FLOAT        specular_ior                          1.5
     FLOAT        specular_roughness_anisotropy         0              [0, 1]
    Transmission
     FLOAT        transmission_weight                   0              [0, 1]
     RGB          transmission_color                    1, 1, 1
     FLOAT        transmission_depth                    0              [0, +inf]
     RGB          transmission_scatter                  0, 0, 0
     FLOAT        transmission_scatter_anisotropy       0              [-1, 1]
     FLOAT        transmission_dispersion_abbe_number   20             [0, +inf]
     FLOAT        transmission_dispersion_scale         0              [0, 1]
     BOOL         transmission_transmit_aovs         *  false
     INT          dielectric_priority                *  0    

  • kick -info <node>.parameter now includes all available metadata for the parameter, including linkability, bounds, help, as well as the type, name, and default value. (ARNOLD-15306)

    $ kick -info openpbr_surface.fuzz_weight
    node: openpbr_surface
    param: fuzz_weight
    type: FLOAT
    default: 0
    metadata:
     help: The presence weight of a fuzz layer that can be used to approximate microfibers, for fabrics such as velvet and satin as well as dust grains.
     max: 1
     min: 0

• Handle update for OSL shader changes: Information about shaders linked to an OSL shader is stored when using interactive render mode, so that any change in those shaders will cause the OSL shader to be automatically updated. (ARNOLD-14983)

• Duplicate node name warnings: Warnings are emitted when adding a node with a name that already exists or renaming an existing node to an empty string. (ARNOLD-12596)

Bug Fixes

• KTOA-974 - Cannot connect operators
• ARNOLD-14735 - OIDN denoiser bucket artifacts during negative-AA progressive passes
• ARNOLD-15380 - [GPU] small memory leak when using AOV shaders
• ARNOLD-15384 - [GPU] memory leak each time an OSL shader is modified
• ARNOLD-15385 - Crash on standard_volume when modifying material interactively
• ARNOLD-15392 - [GPU] small memory leak when using OSL shaders