Painting needs paint brushes and Blender provides a Brush panel within the Toolbar when in Weight Paint Mode.
- In the Data-Block menu you find predefined Brush presets. And you can create your own custom presets as needed.
- The radius defines the area of influence of the brush.
- 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.
- The weight (visualized as a color) to be used by the brush.