Modeling tools are indispensable for leathercraft. When modeling tooling designs, the tools are used as bevelers, shaders, backgrounders, stipplers, etc. They are used on both floral and figure carving for rounding edges, forming muscles, etc. Many more illustrations of their use are shown in
Tech Tips (where the below example came from),
Pictorial Carving,
Figure Carving and
Leathercraft Tools.