Brush

Painting needs paint brushes and Blender provides a Brush panel within the Toolbar when in Weight Paint Mode.

Brush

In the Data-Block menu you find predefined Brush presets. And you can create your own custom presets as needed.

Radius (半径)

The radius defines the area of influence of the brush.

Strength

This is the amount of paint to be applied per brush stroke.

Use Falloff

When enabled, use Strength falloff for the brush. Brush Strength decays with the distance from the center of the brush.

Weight

The weight (visualized as a color) to be used by the brush.