Which tool allows you to paint influence on vertices around the selected bones?

The Weight Brush tool is specifically designed for painting vertex weights around selected bones in a 3D model. This is crucial for character rigging and animation, as it determines how much influence a particular bone has on each vertex of the mesh. When using this tool, artists can adjust the weights to achieve smoother deformations in an animated character, enabling more realistic movements. The ability to fine-tune vertex weights directly affects the quality of the animation, making the Weight Brush an essential tool in the workflow of a 3D artist.

Other options such as the Pencil Tool and Fill Tool are typically used for painting textures or colors rather than adjusting vertex weights, and the Vertex Painter, while it might suggest editing vertex attributes, does not specifically denote the weight painting function required for rigging and animation setups. Thus, the Weight Brush stands out as the primary tool for this specific task.