Convert is used to convert input grooms and guide curves ( strands ) to fibres and back. This is useful for using procedural node to affect the look of a groom or make it possible to groom one set of Fibres with another. If converting from Strands to Fibres it’s recommended to provide the Second input which is the Mesh that the Groom/Guides were originally created on.

0Data Flow or StrandsFibres, Feathers, Braids or Groom/Guides
1Data FlowMesh

Conversion TypeUsed to select if you want Yeti to convert Fibres to Strands, Strands to Fibres, Feathers to Fibres or Braids to Fibres.
Radius of InfluenceWhen converting from Fibres to Strands and the Fibres weren’t originally Strands ( ie. previously converted ) then this is used to specify the radius of influence for the Strands
Braid DensityThis provides a means of modulating the evaluated braid density when converting braids too fibres.


The File node can be used to read geometry data from files on disk - currently only the Alembic file format is supported.

FileThe input file name, standard C string formatting can be used to resolve the frame number, ie. %04d for a four zero padded frame number.
QueryA regular expression used to query for specific object names within the file.
Preserve Scene TransformOffset the objects stored transform with that of the Yeti nodes.


FrameThe frame number to be used if resolving a frame variable in the reference file name.
FPSFrame rate to use when resolving the frame time.
Start TimeOffset the time read from the input file.
Time ScaleUsed to scale the time samples read from the input file.


The Grow node is used to create fibres ( fur/hair ) using input particle locations as the seed for each fibre. Yeti loops over each input particle and determines various potential attributes for each which may include length and direction. The new fibres will follow the final resolved direction ( which defaults to $N ) and will be made up of Segment Length long segments. Grooms and Guides can be used as a second input which are sampled for their length which is applied to the final potential length of a Fibre - this will only set the length of the fibre with a Comb or Guide node needed to set the shape/direction downstream.

0Data FlowParticles
1StrandsGroom/Guide Curves used to control the length of the created fibres.

DirectionSpecify the direction of the fibre, defaults to $N which is the surface normal.
Minimum/Maximum LengthThe shortest and longest possible lengths for the fibres, these may be modulated by any input Strand lengths.
Length MultiplierA means of increasing the overall length of the fibres.
Length BiasUsed to control if the bias between the number of shorter and longer fibres. 0 is evenly distributed, -1 means mostly short fibres and 1 is mostly long fibres.
Segment CountThe number of segments per fibre.
Inherit AttributesDefines a list of attributes, each separated by a space, that will be inherited from the geometry the fibres are growing from.


The Import node is used to reference geometry in the graph - this can be anything that has been specified as an input in the Maya node. The node can represent Geometry, Grooms or Guides and once specified can be connected to the appropriate node inputs to control the flow of the graph. An Import is generally the very first node used as without one there is no base mesh to create the fur.

The Selection parameter is extremely important, and is used to search for the name of geometry being read into the graph. This association is by name only thus if for some reason an object in Maya changes the Import node will fail to resolve the reference. There are many instances where part of a name may change, like when caches are applied Maya adds Deformed to the name, so it’s recommended to use wildcards to make sure any variation on the name is successful.

For example, if you are referencing a mesh named myHerosHead01Shape it might be more flexible to use *Head* - this means not only can the Groom be applied to myHerosHead01Deformed but also anotherHerosHead02Deformed which makes it easy to reuse the Groom for crowds etc.

SelectionThe name of the geometry you want to represent, this can be an explicit name or a name with wildcards.
TypeWhat type of geometry this is going to represent, a mesh, guide curve set, groom, feather or braid.


The Instance node is a way of creating controlled duplicates of geometry, whether mesh or fibres, connected to Input 1 at every point or element in Input 0.

0Data FlowFibres, Particles and Meshes
1Data FlowFibres, Particles and Meshes

Instance ToElements tells the node to instance on a per element ( fibre ) basis where as Points will instance to all the incoming points.
AlignmentEither a variable or static expression used to align the instance.
Alignment VariationMeans of introducing random variation into the resulting alignment.
OffsetPer instance offset, a possible value may be “$N * 0.1” to shift all of the instances 0.1 units away from the surface.
ScalePer instance scale, this could be an expression, eg. “noise($id * 10)”
Scale VariationUsed to randomize the resulting scale.
TwistTwists the new instance around the resulting axis.
Twist VariationVaries each instances twist value.
Up VectorAn up vector in determining the instances orientation.
Axis Of AlignmentDefines what axis in the input object will be aligned to the Alignment vector.


Source ObjectsIn the case where Input1 has multiple input objects you may limit it to just the first, or all of them.
Object ExpressionIf Input1 contains multiple objects this is an expression used to determine which object to use for the current instance. For multiple objects a cycle expression can be used to cycle through the multiple inputs, eg. “cycle($id, 0, 5 )”
Inherit AttributesDefines a list of attributes, each separated by a space, that will be inherited from the geometry the instances are assigned too.
DeformControls if instances will deform to the shape of the fibres being instanced too, this requires input fibres, and the mode set to Elements.
Generate AsAs Input will reuse as much data to create a completely new geometric representation of the object ( original method ), As Instance will try and use the rendering engines instancing implementation.


Point SelectionAllows the user to write a boolean based selection to define which points are instanced too in an element.
Element Point IndexUsed to define which point in an element is used for an instance.

Local Variables

instanceNumThe instance index.
InstanceCountThe number of instances.
vertexNumThe vertex index for the current instance in the element.
vertexCountNumber of vertices in an element.


The Reference node can be used to reference a previously cached Groom off disk - this becomes useful for storing libraries of base results to be used for instancing or other larger scale procedural systems. An animated input can also be used if %04d is supplied for the frame.

Reference FileThe input file name, standard string formatting can be used to resolve the frame number, ie. %04d for a four zero padded frame number.
FrameThe frame number to be used if resolving a frame variable in the reference file name.


The Scatter node is used to randomly scatter particles over the input geometry, the various parameters and inputs can be used to limit the location/density of the scattered points as well as how evenly they are spaced. If a second input is connected this may have an attribute used to control the density of the particles, by default Scatter looks for an attribute named density but any can be used, as long as the Groom Attribute parameter is set correctly.

0Data FlowMesh or Fibres
1StrandsGroom/Guide Curves which may have an attribute painted to control the density.

Density MultiplierA density value is usually defined between 0-1, if you have an input Groom to control the density this is usually the case. This value is a multiplier on top of the base density.
DensityThe density, based on input area. This is overridden if Input 1 is connected.
Lock DensityIn some cases ( such as with clumping ) you need to make sure a specific density is retained even if rendering, this will make sure the Scatter node produces the same points regardless of the Display and Render densities.
SeedA random seed value used to generate the points and also passed through the flow to any other connected nodes that may require random number evaluation.
Groom AttributeThe attribute that defines the density of the points if Input 1 is connected.
Source Object(s)If more than one mesh is imported up stream this provides a means of generating points either on the first mesh, or all of them.
Face SetLimits the creation of source points to faces only contained within the named face set ( if it exists ).
Ignore Region of InterestPoint generation will ignore the bound limits set by the current region of interest, if any.


Base/Tip DensityWill modulate the density of the scattered particles along the length of the input fibre.
Up VectorUsed with the tangent of the input fibre to compute a decent random normal for the resulting particles.


Relax StepsBy default Scatter creates fairly random points, by increasing the relaxation steps the points relax their positions which result in a more even and regular distribution ( which is generally what you need for feathers ).
Obey Face SetToggles whether the relax process is contained within the defined face set or not.