static bool AffordanceBegin(string id, Pose& pose, Bounds handle, bool drawHandle, UIMove moveType)

string id Id of the affordance group.
Pose& pose The pose state for the affordance! The user will be able to grab this affordance and move it around.
Bounds handle Size and location of the affordance handle, relative to the pose.
bool drawHandle Should this function draw the handle for you, or will you draw that yourself?
UIMove moveType Describes how the affordance will move when dragged around.
RETURNS: bool Returns true for every frame the user is grabbing the handle.

This begins a new UI group with its own layout! Much like a window, except with a more flexible handle, and no header. You can draw the handle, but it will have no text on it.