Definitions
The terms below are used throughout this documentation. They are listed alphabetically.
Channel
Extra data stored on strands, either one value per strand (root) or one value at each point along a strand (vertex). Channels are used to drive operator parameters so an effect can vary across a groom. See Working with Strand Channels.
Clump
A group of strands gathered together so they behave as a tuft, as real hair does when it sticks together. See Clump Operator.
Distribution
How and where strands are placed on a surface - the pattern, density, and count of roots. Distribution can be uniform, random, or driven by a map.
Guide
A sparse strand that defines the approximate shape and flow of a groom, analogous to a control cage in mesh modeling. Guides are interpolated to produce dense hair, and most hand editing is done on them. See Hair and Guides.
Hair
The dense, final set of strands, generated by interpolating between guides. A groom may have a few guides but hundreds of thousands of hairs. See Hair and Guides.
Interpolation
The process of generating dense hair from sparse guides by blending the shapes of nearby guides. This is what Hair from Guides Operator does.
Operator
A single step in building or styling hair, with its own parameters. Operators are stacked to create a groom procedurally. The terms operator and modifier are interchangeable; the App uses operator. See Objects and the Operator Stack.
Operator stack
The ordered list of operators applied to an object, evaluated from the bottom up, each one transforming the result of those below it. See The Operator Stack.
Parting
A division of hair into separate regions of flow, as where hair splits along a line on the scalp. See Hair Parting Tool.
Propagation
Creating new strands that grow out of existing strands, used for effects such as feathers and branching fur. See Propagation Operator.
Root
The point on a surface where a strand begins, fixing its position and orientation. Roots defined relative to the surface deform with the mesh, keeping hair attached during animation.
Segment
A short straight piece of a strand. A strand is approximated by a chain of segments between its points; more segments give a smoother curve.
Strand
The general term for a single hair-like curve. Both guides and dense hairs are strands; operators that accept either work at the strand level.
Strand group
A whole-number label on a strand, used to target operators at chosen parts of a groom. See Working with Strand Groups.
Tangent
The direction a strand is flowing at a given point along its length. Hair shading and many effects are computed relative to the tangent rather than a surface normal.
Texture map
An image used to vary a value across a surface, for example to control where hair grows or how strong an effect is. Maps can also be converted into channels with the Generate Strand Data Operator.