Release date: November 410, 2021

Welcome to RenderMan 24.2!

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• Volumes: PxrPathTracer now supports "Volume AggregatesAggregate Volumes".   Volume Aggregates are Aggregate Volumes is a new technique allowing you to render overlapping volumes more efficiently and lower the time to first pixel. It also allows PxrSurface to use a heterogeneous volume in its interior integrator.  See details here: Aggregate Volumes and in the DCC specific documentation sections.
• Volumes: PxrVolume has a new velocityPrimVar parameter. This is more efficient than reading the velocity via a PxrPrimvar or PxrVariable pattern
• Volumes: Adding additional new parameters to PxrVolumeimpl_openvdb: densityScale, densityRolloff, filterWidth, velocityScale

• Lights: Light shaders now have the ability to opt into multiscattering approximation calculations for the new aggregate volume feature

• Integrators: Added support for Path Guiding.  It can be activated in PxrPathTracer and the PxrUnifed PxrUnified integrator via the new risGuiding integer parameter. Path Guiding is currently incompatible with integrator settings with more than one indirect sample, and with PxrPathTracer's 'manual' bxdf sampling mode. Requires light learning to be enabled
• OSL raytype() is now implemented.  The supported ray types are "camera", "shadow", "reflection", "refraction", "diffuse", "glossy", "subsurface", and "displacement"
• Statistics: More stats are available in the JSON report.

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• Lighting: Fix equiangular clipping in presence of infinite lights
• Lighting: Several fixes related to light selection
• Lighting: Fixed a live render bug where the ramp would render backwards initially if begin > end
• Integrators: A crash in the Path Guiding feature of PxrUnified has been fixed
• BxDFs: Added labels for glass parameters to PxrLayerSurface to match PxrSurface: Shading Tangent, Manifold Walk IOR, and Anisotropy
• BxDFs: Fixed presets in LamaConductor
• OSL: Silenced a debug message that was slowing down regex_search()
• OSL: Improved OSL metadata tokenization to correctly handle <primvar:varname>
• OSL: Fix out-of-bounds vector access when a spline is provided with only a single control point
• Alembic: Fix for incorrect renders that could show up with polygonal input data with normals
• Geometry: Fixed a memory leak for the case of general polygons which also occurred for pretessellated subdivision surfaces
• Volumes: indirect visibility of volumes now correctly takes into account scattering events that occur within the volume. Previously indirect visibility was only checked at volume interfaces, which meant that surfaces within volumes that also enclosed the camera could wrongly reflect indirect invisible volumes
• Checkpointing: When using the new variance metric, fixed a problem that prevented resuming from a checkpoint
• Rendering: Fixed an issue that if you edited the shutter value, the framing and sampling unexpectedly changed
• Rendering: Add support for FloatVectorAttribute when setting metadata for EXR output
• macOS: Don't crash on Macs with AVX512 instruction set support

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• Shading: Fixed a known look difference between CPU and GPU portions of XPU
• BxDFs: Fixed the potential for NaNs when using the fuzz lobe of PxrSurface
• Textures: Fixed issue with primitive variable substitutions into texture filenames
• Textures: Fixed artifacts that arise in XPUGPU mode when texture cache size is small
• Textures: If the memory specified for ptex is too small, instead of emitting a warning, use 128MB and render without a warningXPU now shares the same minimum ptex and non-ptex texture cache sizes RIS.  In the case the user sets a minimum texture cache that is lower than our internal minimum we use it and do not display any warning for both ptex and non-ptex texture caches
• OSL: Robustly handle the case if memory allocation fails when setting up the color system for OSL
• Patterns: Fixed a crash that would occur if '-' was used in the name of a pattern
• Performance: Fixed cases where CPU + GPU would sometimes render slower than the GPU alone
• Geometry: Fixed a problem that could result in a crash when editing materials on curves
• Lighting: Correctly initialize default values for light parameters in XPU

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