YETI TUTORIALS

Introduction

 
Definitions

Terms used in this document and their definitions and synonyms are listed below.

Yeti Node:

Where the graph is created to manipulate hair strands using internal nodes.

Groom:

 Yeti’s guides that control the hairstyle and its attributes.

Graph:

A graph is made of internal nodes that create and deform the hair fibers.

Nodes:

Each node has distinct functions and deformers, and each node has specific inputs.

Data types

Yeti is able to manipulate some types of data within its graph, through its nodes. Each node accepts specific data in each of its inputs so that it can apply its modifiers or operations. The types it handles within the graph are:


 

Geometry: Meshes made of polygons. Yeti only supports meshes that have UVs. Curves and NURBS are not supported directly, only through Guide Sets.

Fibres: Hair curves which will be guided by the strands and will receive the effects of the nodes of the graph.

Strands: How Yeti uses Grooms or Guide Curves within their tree. They carry their own parameters and attributes, and there is a radius of influence for each strand. They serve to guide and transpose parameters for deformers (nodes like comb, curl, scraggle) of the fibers. However, objects or feathers cannot be instantiated directly on strands.

Particles: The Scatter node generates particles by spreading them on the surface. Then, a node of Grow could make the fibers grow or a node of Instance could instance other geometry of feather on each particle.

Feathers: Is the procedural Yeti’s system responsible for creating a feather formed of fibers.

 

Yeti also works with specific types of data for its attributes. The two types supported are:

 

Float: A single number that accepts decimal units, could be positive or negative.

Ex.: 1 , 1.5 , -1.5 , 0.01 …

Vector: Set of three Floats that form a vector, useful for sets of [x, y, z] such as Normal or Positions.

Ex.: [0,1,0]  ,  [ -1, 0.1 , -0.1 ] …

 

Yeti performs the automatic cast between Float and Vector. It means that Yeti automatically converts a Float to Vector and vice versa.


If the field requires a Vector and the we write a Float, this value will be written into the three values ​​in the Vector:

Example:

Float 2 become Vector [2,2,2]

Float 1.34 became Vector [1.34, 1.34, 1.34]

 

If we write a Vector where a Float is expected, then only the x coordinate is casted to Float.

Example:

Vector [1,2,3] became Float 1

Vector [0.4 , 0 , 1] became Float 0.4

 

To access a specific Float value inside a Vector, we can use V [0], v [1] or v [2] to access the x, y, and z values ​​respectively.