A channel is a fluid property, for example velocity. The fluid's velocity channels is available as a series of vertex maps and can be used to visualize differences in the property's values. This way it is possible to achieve realistic shading effects. Please go to → "Mesh Channel Vertex Maps" to learn how to use channels with materials and shaders. For a workflow description how to use weight maps please visit → "Mesh Weight Vertex Maps".
Speed
Speed is the combination of the individual "Velocity X | Y | Z" values. Please see here for a → workflow description.
Velocity X | Y | Z
Instead of the combined speed value it is also possible to visualize the individual XYZ components. Please see here for a → workflow description.
Vorticity
Vorticity is used to show the fluid's swirls and vortices. In order to use this channel it has to be activated under → Fluid > Fluid > Compute Vorticity before the simulation! Please see here for a → workflow description.
Age
This channel shows the particles' age distirbution. If all particles share the same age the fluid will have a uniform colour. Please see here for a → workflow description.
Weights
If the mesh contains multiple fluids or emitters you will see weight vertex maps. These maps can be used for blending and mixing effects of differently coloured fluids. From the dropdown menu you can choose whether the maps should be created from fluids or emitters. For fluids, all containers have to be linked to one single mesh in order to make the maps work. Please see here for a → workflow description.
Scale
Every channel has a "Scale" parameter for controlling the vertex map's strength. This is useful to enhance differences in the channels and to create more contrast.