• Added ignore_config_files option to init flags that allows the
  application to ignore Embree configuration files.
• Face-varying interpolation is now supported for subdivision surfaces.
• Up to 16 user vertex buffers are supported for vertex
  attribute interpolation.
• Deprecated rtcSetBoundaryMode function, please use the new
  rtcSetSubdivisionMode function.
• Added RTC_SUBDIV_PIN_BOUNDARY mode for handling boundaries of
  subdivision meshes.
• Added RTC_SUBDIV_PIN_ALL mode to enforce linear interpolation
  for subdivision meshes.
• Optimized object generation performance for dynamic scenes.
• Reduced memory consumption when using lots of small dynamic objects.
• Fixed bug for subdivision surfaces using low tessellation rates.
• Hair geometry now uses a new ribbon intersector that intersects with
  ray-facing quads. The new intersector also returns the
  v-coordinate of the hair intersection, and fixes artefacts at junction
  points between segments, at the cost of a small performance hit.
• Added rtcSetBuffer2 function, that additionally gets the number of
  elements of a buffer. In dynamic scenes, this function allows to
  quickly change buffer sizes, making it possible to change the number of
  primitives of a mesh or the number of crease features for subdivision
  surfaces.
• Added simple 'viewer_anim' tutorial for rendering key
  frame animations and 'buildbench' for measuring BVH (re-)build
  performance for static and dynamic scenes.
• Added more AVX512 optimizations for future architectures.