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  • 'it' now has expanded exposure controls allowing better viewing of HDR images.
  • Mesh lights now support the same shadow controls and shadow linking as the analytic lights.
  • Improvements to light selection on scenes with many lights should improve render times.
  • Performance improvements to volume rendering, especially very sparse volume fields and/or single scatter volumes.
  • OpenEXR texture reads (.tex as EXR) are faster.
  • Added more controls to texture patterns:
    • This includes:
      • PxrTexture
      • PxrProjectionLayer
      • PxrLayeredTexture
      • PxrMultiTexture
      • PxrNormalMap
      • PxrBump
    • Added 3 new parameters to texture patterns:
      • int mipBias: bias mip selection, negative numbers bias lower resolution while positive numbers bias to higher resolution textures.
      • float maxResolution: clamp mip selection, useful to prevent loading of higher resolution mipmap levels.
      • optimizeIndirect: sets to an inexpensive Box filter on indirect hits, except on PxrBump where the filter is fixed.
    • The user attributes, "int texturemipbias" and "float maxtextureresolution", will override these settings. 

Miscellaneous Changes

  • GPU Denoise requires CUDA 7.5 and compatible hardware.

  • For refraction, extinction and ssAlbedo are unconnectable on PxrSurface

  • Added support for baking with displacement
  • Improved precision of PxrRamp inputs
  • PxrPortalLight: now supersamples the input texture, leading to less potential pixelization on low resolution textures
  • PxrSphereLight's intensityNearDist is now more correct/precise.
  • Path Traced Subsurface options in PxrSurface now converge more quickly for high phase values
  • Lighting Services: 
    • Minor changes to horizon culling of lights and clusters to the light selection algorithm
    • Additional code robustness for lights: Fixed crash in cases where mesh lights were instanced
  • PxrPortalLights, added more protection against slightly negative dot products in the portal sample function.
  • PxrMarschner lobe picking improvements, this reduces the variance, especially for high albedo hair
  • Memory optimizations in KD tree representation of volumes

  • Optimizations for volumes in the case of low density volumes
  • Updates to remove subsurfaceZeroScatterAttenuation to make sure that PxrLayerSurface reflects the new approach in PxrSurface
  • Prevent PxrOcclusion from calculating occlusion for infinite lights.
  • Add new RixShadingContext::GetNearestHits method with excludeSubset parameter.
  • Reduced memory usage when baking complex scenes with PxrBakePointCloud.

  • PxrDisney "ClearCoat" lobe has been renamed "Clearcoat" for output to standard LPEs used by other shipped materials.
  • Thread contention has been reduced when emitting many RiObjectInstances from multiple threads.

  • Added new API calls that Display and Sample filters can use to perform image processing (e.g., for NPR) across bucket boundaries.