• fixed a bug where sampling fibres at a parameter of 0.0f would result in NaN’s when additional knots where present (required by some rendering engines).
  • fixed a thread safety issue with generating UUID’s that was causing instability in the Instance node.
  • updated Guide and Scraggle to take into account additional knots required by various rendering engines.


  • fixed a bug which was causing additional nan’s in feather output (causing Arnold to complain about 0 points).


  • updated VRay plugin for VRay 3.52 release.
  • fixed bug which caused instability during out of order evaluation when loading grooms.
  • strand length display now correctly obeys the isolate selected option.
  • added -licenseStatus and -batchLicenseStatus to pgYetiCommand to query whether a license is currently being used or not.
  • fixed an issue which was causing strands to increase their length in some situations when used with particular brushes.
  • zero length barb samples are now corrected for in feather expansion.
  • fixed an index overrun issue when computing feather tangent space which led to potential nan’s in feather output (causing Arnold to complain about 0 points).


  • fixed a bug introduced in 2.1.10 that was causing the Scraggle node to generate erroneous results when outputting fibres to rendering engines expecting additional knots for curve interpolation.


  • fixed a handedness issue with Redshift extension to ensure poly faces are pointing in the correct direction.
  • deforming instances now correctly use a world space up vector.


  • fixed an issue with updating up vectors causing the Curl node to change shape on rotation.
  • fixed an artifact in the Scraggle node which would cause unwanted twisting on longer hairs.


  • Yeti will now replace spaces in node names with underscores to avoid errors when saving graphs.
  • Fixed an issue with tangent computation in Attribute node.
  • Graph evaluation is now ignored completely when the Yeti node is hidden in VP2.0.
  • input rotation is now correctly applied to Instances when not deforming.
  • fixed a bug that was causing guide sets with a large number of elements to take an extremely long time to retreive set member names.
  • Width attribute is now correctly exported to the rendering engine when Feathers are used.


  • resolved issue with mapped attributes not being transferred to instances correctly.
  • feathers now correctly export inherited attributes after expansion.
  • feather barb count is now based on a rest position vs. dynamic length which avoids motion blur issues.
  • introduced Barb Density parameter which is more intuitive than Barb Spacing for feather creation. Barb Spacing remains the same and will produce the same output if Density is left at 1.0 but it’s behaviour will change in the future.
  • fixed a bug in the Instance node which was causing duplicate objects to be returned when Object Selection was set to All.
  • Yeti node correctly obeys VP2.0 visibility overrides including Display Layers.
  • Smooth brush works correctly when used on a deformed groom.


  • Comb and Sculpt now work on deformed groom positions.
  • exported attributes are now exported as Vectors for VRay as Custom Map Channels expects vectors to be accessed via VRayUserColor vs. VRayUserScalar.


  • feathers now export the surface S and T values as their default UVW coordinates for VRay.
  • fixed sizable memory leak introduced via VP2.0 SubScene override implementation.
  • fixed a bug in Blend node that would cause a crash if a second input was evaluated to NULL.
  • updated Blend node to use object indicies vs. names so referenced graphs may be blended correctly.


  • fixed out of range access in Groom context.
  • fixed a bug in Groom context where NULL was being incorrectly checked.
  • fixed a race condition introduced with threaded DSO loading in Arnold.


  • refactored attribute mapping to be tracked on a per geometry type basis.
  • object selection is now retained when rendering with VRay.


  • inherited attributes in the Grow node are now correctly allocated.
  • resolved memory leaks related to VP2.0 implementation.
  • feathers are correctly update when vertices are edited.
  • updated MtoA extension to be compatible with MtoA 1.4.0 API.
  • surface UV’s are set as default for Redshift.
  • additional UV set named featheruv exported for Redshift which can be accessed via the UV Set Override on the Place 2D Texture node.
  • fixed an issue where object id’s weren’t being maintained when read from a cache.
  • fixed feather proxy drawing in shaded view.


  • Redshift support for Windows and Linux.
  • particles are now visible in Maya 2016.
  • feather objects correctly follow selection colour.
  • Yeti will replace : in referenced node names with _ when caching.


  • fixed an issue with a cyclic evaluation of guide curves which would cause excessive computation.
  • feather texture coordinates are available as a Vector attribute named feather_uvw for VRay.
  • added an example file that shows how to access parent S and T coordinates on instances for Arnold.


2.1.0 RC

  • corrected a bug caused by objects being removed from data streams incorrectly.
  • feather draw instability in VP 2.0 fixed.
  • renamed feather display type Skeleton to Proxy.
  • parent attributes are correctly transferred to feather instances.
  • Displacement node correctly updates rest offset correct which resolves an issue which causes instances to be transformed incorrectly.
  • PRMan and 3delight support for Maya 2017.

2.1.0 b04

  • feather object correctly drawn with correct width in the viewport.
  • thick fibres correctly drawn in Orthographic Viewport cameras.
  • Yeti graph user variables are now stored as dynamic attributes to capture multiple samples when animated.
  • mirror brush re-implemented for Sculpt and Trim tools.
  • “Mirror Plane” renamed to “Mirror Direction” for better UX.
  • Yeti graphs are refreshed after flushing the texture cache to ensure any new textures are read.
  • refactored object iterator to ensure graph objects retain their correct order when using the Merge node.
  • fixed custom Map channel implementation for VRay.
  • resolved an issue which caused the graph to be evaluated even if the node was hidden resulting in really bad performance.
  • Display Output and Draw Feedback now correctly updates the Viewport.
  • added feather instancing example.

2.1.0 b03

  • fibres are drawn with their correct width in the viewport plus full support for VP2.0 anti-aliasing, SSAO and shadows.
  • distribution now includes MtoA extension for Maya 2017.
  • VRay 3.40 build for Maya 2017.

2.1.0 b02

  • Maya 2017 build.
  • middle mouse button will invert the strength of the brush while grooming.
  • using the Fill tool with the Remove brush correctly updates the display once all strands have been removed.
  • fixed a bug which would cause Maya 2016 to crash on Linux when attempting to add new objects to the graph.
  • Scatter node has been optimized for larger surfaces.

2.1.0 b01

  • drawing has been completely refactored to fully utilized Maya’s Viewport 2.0 framework.
  • selection status of Yeti object is now show via a bounding box vs. changing the colour of the object.
  • shelf buttons now try to ensure that the Yeti plugin is loaded.
  • added parameters for Vray to toggle smooth splines and segment tesselation lengths for them.
  • added Keep On Surface attribute which allows the user to toggle strand collisions with it’s parent surface.
  • Groom attributes are correctly blended with corrective grooming.
  • Attribute paint feedback in the viewport to indicate the currently active attribute.
  • Strands that will be affected by the current brush now have a subtle highlight in the viewport.
  • Curl node has a new Maintain Length parameter which defaults to off, so U and V scale will correctly scale the curls in the U and V axis.
  • Length parameter on the Curl node is a more accurate representation of an actual revolution of a curl.
  • Added Phase Random and Length Random parameters to the Curl node to provide the ability to create less uniform curls.
  • Added Step Size parameter to any sets containing Guide Curves to control the detail of resulting guide curves in the Yeti graph.
  • Proxy feathers are now shaded in the Viewport for better visualization.
  • added Barb Linearity parameter to the Yeti Feather primitive which can control how straight the actual barbs appear.
  • multiple file names can be used for caching seperated by the pipe (|) symbol, please refer to Working With Caches for more details.
  • custom map channels are supported with VRay using the Attribute node and VRayUserColor.
  • Undo/Redoing while grooming will no longer invalidate strand selections.
  • Direct X support on Windows has been added.
  • added particle rendering support for Arnold.
  • added particle rendering support for Renderman.