7 March 2016

This is feature release, with selection rendering, new and enhanced shaders and numerous core enhancements.

  1. Get the install files on Solid Angle Downloads.
  2. Follow these installation instructions.

This release uses Arnold and OpenVDB 3.0.0.

Binaries available for the following Houdini, Houdini FX or Houdini Education production builds:

  • 15.0.393
  • 15.0.347
  • 15.0.313

and for the following platforms:

  • Linux x86_64 (gcc4.4 for H14, gcc4.8 for H15)
  • Windows 7 x64 (vc11)
  • Mac OS X 10.8+

Please note that Houdini Apprentice and Houdini Indie do not support third party renderers and thus cannot run HtoA.

  • SSE4.2 optimizations: We have raised our minimum CPU requirements from CPUs needing to support the SSSE3 instruction set to SSE4.2. This allows us to start taking advantage of the additional SSE4 instructions to further optimize Arnold. Already we are seeing a slight speedup in several areas. For instance, the Hosek Sky shader is now 5% faster. (core#2625, core#5051, core#5053, core#5056)
  • Faster OpenVDB motion blur: Rendering of motion blur on CPUs with many threads is now faster. The speedups depend on the specific scene and the CPU, but we have often seen 2x faster, and even 10x faster in some cases. Additionally, rendering of OpenVDB files with separate velocity grids for the XYZ components is now also up to 2x faster, so that merging the grids into a single vector velocity grid is no longer required for good performance. Merging the grids in advance still helps to make the file loading a little faster. (core#5103)
  • Faster gobo shader: The number of shader evaluations in the gobo light filter has been greatly reduced. We are seeing 20% faster renders in simple scenes with a light and a gobo. (core#5070)
  • Faster textures: AiTextureAccess() is now much closer (though still not equal) in performance to AiTextureHandleAccess(). We have also made AiTextureHandleAccess() faster in certain situations. (core#3192, core#3699, core#5069, core#5068)
  • Default texture cache size increased to 2GB: The default setting for options.texture_max_memory_MB has been increased from 1GB to 2GB. This can help improve performance on texture heavy scenes. (core#5101)
  • Quad and disk light spread: Quad and disk lights can now emit light focused in the direction along the normal. The default spread value of 1 gives diffuse emission, while lower values focus the light more, until it becomes a laser like beam at value 0. Low spread values can be noisier than the default high spread, so be careful when using them. Barbs in the quad light and disk light gizmos represent the spread an will give a visual cue of the light distribution in the viewport (core#5119, htoa#755)
  • Photometric light radius: Photometric lights now include a radius parameter with which softer shadows may be obtained in a manner similar to point lights or spot lights. Defaults to 0, which matches this light's original behavior. Note that IES files only store far-field photometric values, so it's meaningless to use them with area lights, and abusing the new radius parameter can make things look strange. The intent of adding this radius is to achieve slightly soft shadows rather than razor sharp shadows in a manner that is acceptable for VFX use. (core#5121)
  • More shader parameter conversions allowed: It is now possible to link a shader that outputs a float to a shader that takes in an integer type and vice versa. Likewise, several other useful types of conversions are also now allowed. (core#5058, core#5095)
  • Deep EXR driver support for append / checkpointingdriver_deepexr now supports append on to skip rendering buckets that were saved in a previous interrupted render. Currently this only works for tiled mode, not scanline. Note that since Nuke only works with scanline deep files, if your output deep files are tiled you will have to convert them with oiiotool input_tiled_deep.exr --scanline output_scanline_deep.exr (core#4863)
  • Improved deep EXR driver support for volumes: Deep volumes are now written with higher precision using less samples, which results in much more accurate and smaller deep EXR files, with size savings of 50 to 75%. (core#5102, core#5113, core#5114, core#5120, core#5135)
  • Fewer warnings: A number of pedantic warnings have been removed in order to declutter log files: nonexisting shader paths, camera matrix overriding handedness, deprecated RGB AOV, empty polymesh node, UV array compression, ignoring mesh with all faces invisible, user normals on subdivs, too many messages of given type. (core#5042)
  • Updated to RLM 12.0BL2: We have upgraded the license server and the external library controlling the licensing subsystem from version 11.3BL1 to 12.0BL2, a more stable release fixing various crashes, bugs, hangs and memory leaks. (core#5014)
  • UVs in quad light filters: Light filter shaders on quad lights can now use sg->u and sg->v to retrieve the UV coordinates on the surface of the quad light. (core#5122)
  • Support for independent MPlay sessions: You can now specify an MPlay Session label on the ROP which is useful with multiple workspaces. (htoa#747)

  • New Curvature shader: This new shader will sample around the shading point to output convex and concave curvature in the red and green channel respectively. You can adjust the radius, falloff and spread of the curvature sampling as well as specify a trace set to exclude or include objects. This shader is useful to create procedural wear or dirt maps in conjunction with a noise shader. (csp#92)
  • New Checkerboard shader: A configurable checkerboard pattern shader with a reasonable automatic default filter width to reduce aliasing. The filtering can be further tweaked, as well as the frequency and contrast. (csp#93)
  • Enhanced Shadow Matte shader: The shadow_matte AOV now supports multiple light sources in the scene, and relative light intensity and color are now taken into account. A new shadow_diff AOV has been added which allows to reduce shadow opacity by adding it to the direct component in compositing. Lastly, added support for backlighting. (csp#91)
  • Render selection only: When enabled on the ROP, only the selected OBJs, lights will be rendered. If a SHOP material or VOP is selected, only the objects that have this material assigned will be rendered. You can chose how the remaining objects will be rendered. The default is to skip the export the remaining objects entirely, but you can also render them as phantom (invisible to camera rays) or as matte. (htoa#745)
  • Garbled ray estimations with a ROP create script (htoa#689)

  • Variable 'deepexr_layer_tolerance' referenced before assignment (htoa#749)

  • Fixed glitch in Volume Collector UI (htoa#748)

  • Temporary .ass file are now deleted immediately after reading unless the HTOA_TMP_DEBUG environment variable is set (htoa#751)

  • The scale component of the camera transform is now removed to avoid 'invalid camera matrix' errors (htoa#754)

  • Ensure existence of HTOA_TMP before every write (htoa#753)

Incompatible changes
  • Require SSE4.2 CPU: We now require CPUs that support (at least) SSE4.2 instructions. On older computers that do not support these instructions, Arnold will immediately abort on startup. (core#2625, core#5053)
  • Internal reflections in standard shader: The enable_internal_reflections parameter previously did not ignore all internal reflections, and incorrectly ignored some other reflections, which is now fixed. (core#5136)
  • Specular roughness: When using very low or zero roughness in the standard shader or microfacet API functions, reflections will be sharper than before, where previously they were too blurry. (core#5067)

See also the Arnold release notes for the full list of core enhancements.

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