Guide Channels
Guides in Ornatrix are used to define the shape of hair without having to deal with thousands of strands individually. By default, guides consist of information such as vertex positions, root on surface information, and strand selection. Sometime it is useful to add extra information to guides to control some additional hair properties such as clustering, curling, or local dynamics and animation.
Channels allow users to add extra data to guides that can be used later on. There are two types of guide channels used by Ornatrix: root and vertex channels.
Root channels hold a single data value per every root (strand). This is a compact way of defining information that is uniform for every strand. It can be very effective for controlling properties that usually don't vary along strand length (such as hair density and dynamics properties).
Vertex channels hold per-vertex data. Every knot that defines the shape of every strand will have a value attached to it. This is more memory consuming than root channels and it allows you to control anything at any point on the hair model. Vertex channels can be useful to control clustering, frizz, and hair shading.
Using Guide Channels
Channels can be made very helpful and even irreplaceable in many places during the process of hair management.
Guide channels can be created or removed through Edit Guides modifier. Some modifiers allow you to manipulate channels procedurally to achieve some modifier-related goal. For example, thickness channel can be modified by some modifiers to make some strands fill in more space than others.
The first root and vertex channels are reserved for internal Ornatrix selection. Therefore, these two channels cannot be removed. They can, however, be edited and assigned but Ornatrix can change their state at any time.
Example
Let us take an example of using a channel to control strand-based clustering of dense hair. Whenever you convert guides to hair, the dense hair model inherits the guides' channels. To determine a channel value for a specific strand/vertex in the dense model Ox will look up the closest guide to that strand and use its value. Therefore you can directly modify the strand clustering by simple changing the guide channel value of a guide strand that dense hair will be later clumped to.
Begin by adding a separate per-root (or per-vertex) channel to your guides in the Edit Guides modifier. You can rename this channel to "clustering" so it can identified easily later on in the pipeline. Now you can go in and modify the channel value for clustering using a brush or directly from roots or strands sub-object rollout. Assign this new "clustering" channel to the value map in strand clustering modifier.
Note how when you edit clustering channel in Edit Guides modifier (if show end result mode is on) you can see clusters changing size dynamically. This is a small demonstration of what kind of control channels can add to your workflow.
The best strategy is to name channels according to their purpose, and organize so you know clearly which channel performs which operation.