The type of field and its attributes specify the kind of effect it has. You can set the field attributes before you create the field, or you can create a default field and set the attributes after creation.
To set field attributes before creating the field
To enter a value that exceeds a default slider range, type the value in the text box.
To edit field attributes after creating the field
You can animate field effects by setting the field attribute values with keys or expressions. To turn off the effect of a field at some frame, you can key the value of its Magnitude attribute to 0. Make sure the key Tangents are Stepped if you want the Magnitude to change abruptly to 0 rather than with a gradual interpolation.
Set Volume Control Attributes and Volume Speed Attributes
In the Attribute Editor and the Create Emitter option window, attributes not applicable to a volume shape are dimmed. However, the Channel Box does not support dimming. We recommend you use the Attribute Editor instead of the Channel Box to edit volume field attributes until you become familiar with the attributes that apply to each volume shape. Some Volume Control Attributes, including, Volume Trapping, Axial Magnitude, and Curve Radius attributes are only available in the Attribute Editor.
To set Volume Field Attributes and Volume Speed Attributes