MAXtoA 5.7.6: USD improvements, faster volume intersection, faster baking, and Cryptomatte on GPU

[Stephen.Blair]

MAXtoA 5.7.6.0 is a feature release using Arnold 7.3.5.0.

Installation

• Download Arnold for 3ds Max from your Autodesk Account. See Download Arnold for more information about downloading MAXtoA from your Autodesk Account.
• Follow these installation instructions.

Enhancements

• Support Isolate Selected for materials and maps: Isolate Selected in the Arnold RenderView now works for materials and maps as well as objects and lights. To use this, make sure no objects or lights are selected, and then select one (or more) materials or maps in SME. The selected materials and maps are rendered in the Arnold RenderView, making it easier to debug complicated shader trees. (MAXTOA-1852)

• MAXtoA Toolbar improvements: The MAXtoA toolbar has been enhanced to give more feedback and better UX; the buttons for rending in ARV will now restore the ARV window if it was minimized, and they will be highlighted to indicate the rendering state of ARV. (MAXTOA-1863)

• Improvements to ASS export: When you export an ASS File, the render region is not exported if it is not used. (MAXTOA-1861)

• Optimized Cryptomatte and GPU support: Arnold now has an internal implementation of Cryptomatte that adds support for GPUs and improves performance on CPU. Cryptomatte now consumes less memory for samples, making it easier to use higher AA settings, progressive rendering, and adaptive rendering (when properly used with FIS). In a simple scene rendered at 640x480 resolution with three cryptomattes the below table shows improvements in peak memory. (ARNOLD-11042)

CPU	7.3.4.1	7.3.5.0
fixed-AA	1346MB	442MB
progressive	3433MB	532MB
adaptive	8584MB	441MB

GPU	7.3.4.1	7.3.5.0
fixed-AA	-	799MB
adaptive	-	810MB

• Corrected clamping of OpenPBR metallic lobe: The OpenPBR metallic lobe Fresnel previously exhibited energy gain when the specular_weight parameter was increased above 1. This has been corrected so that the Fresnel conserves energy in this case, saturating to a mirror reflection in the limit of high specular_weight.

• Improved instancing in the alembic procedural: Instanced geometries are now better handled in Alembic. This fixes the known issues with make_instance, which is now enabled by default. (ARNOLD-15209, ARNOLD-8364, ARNOLD-8924, ARNOLD-7818)

• Faster OpenVDB volume intersection: Intersecting OpenVDB volumes are optimized for many-cores. Scenes where volume::intersection is a sizable component of render time can see large speedups. One scene where it accounted for 73% of render time on a 128-core machine saw the volume::intersection time drop to 16% of total time, for an overall 3x speedup in render time. (ARNOLD-15448)

• Faster uv_camera baking: The uv_camera.grid_size default is now 0 instead of 16, where 0 specifies that the grid_size is automatically chosen. Using the new default, baking a sphere with 800k triangles is now 6.5x faster than the previous default. (ARNOLD-15441)

• Add more options settings to image metadata: Images with metadata, such as EXR files, now include arnold/AA_samples_max, arnold/AA_adaptive_threshold, arnold/fis_filter, and arnold/fis_filter_width metadata. (ARNOLD-15521)

• [GPU] Support element linking of array parameters in ramp shaders: Arnold GPU now supports the linking of individual ramp parameter components for the position, value, color, and interpolation parameters. (ARNOLD-7120)

• OSL version 1.13.3.0: OSL has been upgraded to version 1.13.3.0. See OSL release notes for details. (ARNOLD-15319)

• MaterialX OSL closure support: the OSL closures defined by MaterialX (v1.38) for definition of layered physical materials have been ported to Arnold. For example, all the closures needed to implement the OpenPBR are now available in OSL. See OSL Shaders for more information

• Limit node update recursion: Previously, node updates were propagated up the parent chain for all node types. We now do this for shape nodes only. This can improve node update time. (ARNOLD-15492)

• Avoid unnecessary node updates: Resetting a node parameter to the current value will no longer cause a node update. (ARNOLD-15402)

• Per-parameter update dependencies: Previously, a node update dependency caused a node to be updated whenever the dependency node was modified. We now define these dependencies based on parameters, so the node update is triggered only when one of the specified parameters on the dependency node was modified. (ARNOLD-15483)

Incompatible Changes

• Missing dependencies: Custom nodes must declare all dependencies. Now that Arnold uses per-parameter dependencies, any missing dependencies will result in invalid data that may cause crashes or hangs. Also, shaders that depend on render camera values must declare a dependency on options.camera so that the shader is updated when a new camera is set. (ARNOLD-15483)

Bug Fixes

• MAXTOA-1832 - When exporting to .ASS file from the File->Export dialog (not when using the Archive function in the Render dialog), some data was missing, even when Options had been selected. The resolution was always incorrectly exported as 1x1 pixel, and the background color and environment maps were missing. This has been fixed.

• MAXTOA-1862 - MAXScript errors with Save to Previous for 3ds Max 2023

• MAXTOA-1868 - When using Bake/Render to Texture, the metalness of OpenPBR was not exported correctly.

• MAXTOA-1871 - In some cases - notably when rendering from MaxScript - the first render was black.

• MAXTOA-1873 - The state of the MAXtoA toolbar was not restored correctly when Arnold was not the active renderer, causing the toolbar to appear even after being hidden by the user.

• ARNOLD-11891 - Random crashes when using the Maya hypershade

• ARNOLD-15542 - Crash when modifying light group array on a mesh with instances

• ARNOLD-15478 - [GPU] Hangs and crashes with uv_camera

• ARNOLD-15454 - Support overriding a user property on an instance if defined already on parent

• ARNOLD-11794 - Vector type shaders render black when assigned to a shape

USD Enhancements

• Hydra mode in the usd procedural: A new parameter hydra can be used to render the USD data through a Hydra framework. This supports interactive updates, and can be used to reproduce the same behaviour as a Hydra render delegate (usd#2109 usd#2107 usd#2019 usd#2017 usd#2003)

• transform_keys primvar: When the primvar arnold:transform_keys is set, it controls the number of time samples used for the matrices of Arnold nodes (usd#2111)

• Arnold Cameras in Hydra: Arnold cameras (vr, cylindrical, spherical, uv, fisheye) are now supported in Hydra. You create the Arnold cameras as USD built-in cameras, with a string primvar arnold:camera that specifies the Arnold camera type. (usd#1738 usd#2082)

• Improved USD export that better supports Hydra: USD exports now support Hydra, so that scenes from Maya or 3ds Max now render as expected in Houdini Solaris.

  • usd#2000 - Write light filters through node graphs so they can be rendered in Hydra
  • usd#1965 - Write color manager attributes in the RenderSettings primitive
  • usd#2008 - Write spot and photometric lights as UsdLux schemas
  • usd#2030 - Write background and atmosphere shaders under a node graph for hydra support
  • usd#2031 - Write AOV shaders under a node graph for hydra support
  • usd#2025 - Write imagers through node graphs for hydra support
  • usd#1987 - Author familyName and familyType in GeomSubsets written as USD
  • usd#2080 - Author animated shader attributes in a way that they can render in hydra
  • usd#2047 - Shaders exports should be bound to a material

• Fixed mismatches between USD and Hydra renders: Several changes were done, either on the procedural or the render delegate, in order to have a consistent behaviour in both code paths.

  • usd#1974 - Delegate should only create default shaders when needed
  • usd#1959 - Improve translation of normals and primvars in hydra
  • usd#1946 - Support color space in materialx for hydra
  • usd#2042 - Follow hydra normals skinning behavior in the procedural
  • usd#2055 - Support animated curves orientations in hydra
  • usd#2053 - Visibility and sidedness attributes not supported in Arnold native hydra prims
  • usd#2061 - Support arnold light groups in Hydra
  • usd#2086 - Compute FOV in the procedural and hydra in a similar manner
  • usd#2057 - Add ginstance support in hydra and fix a data race issue
  • usd#2067 - Do not author useless "normals" user data in meshes/curves through the procedural
  • usd#2010 - Support TreatAsPoint in spot lights
  • usd#1979 - Support treatAsPoint in Hydra photometric lights

• UsdPlane support: UsdPlane primitives were previously ignored, and are now rendered in Arnold. (usd#2058)

• Improved support for ArnoldProceduralCustom primitives: ArnoldProceduralCustom primitives are now supported like other geometric primitives, including instancing and visibility settings. (usd#2064)

• Profiling / Stats: Render settings can now specify filenames to output arnold profiling or stats files (usd#1118)

USD Bug Fixes

• usd#1982 - Fix subdivision when primvars are set in parent primitives
• usd#1997 - Apply correct amount of transform keys when xformOp is set on parent prims
• usd#1972 - Ensure subdivision is disabled when subdiv iterations is equal to 0 in Hydra
• usd#2015 - Support hydra points with empty widths
• usd#2084 - Imagers should be applied to all drivers
• usd#2105 - Ensure the Arnold scene isn't modified after a Hydra batch render started
• usd#1961 - Random curves width in Hydra when radius primvars are authored
• usd#1977 - AOV shaders not set properly in hydra mode of the scene format
• usd#1984 - Cylinder lights not taking normalization into account through USD
• usd#1994 - Fixed hydra errors with varying topologies, and incorrect velocities in first renders
• usd#1992 - Support hydra skinned positions with more than 3 keys
• usd#2027 - Fix faceVarying normals interpolation in the procedural when the mesh is left handed
• usd#1837 - Fix motion blur of instanced skinned geometry with animated parent matrix
• usd#2037 - Improve instances and objects motion blur coherence
• usd#2078 - Ensure the hydra render callback is always invoked
• usd#2094 - Support material interactive updates in the procedural
• usd#2092 - Fix interactive update issue when prims visibility is tweaked in the procedural
• usd#2102 - Remove hydra warning subdiv_iterations: use type BYTE, not INT