A handheld controller and a system for modeling movement of fingers about the handheld controller is disclosed. In an embodiment, the handheld controller generates signals for, and acquires touch and infusion data. In an embodiment, a processor creates a heatmap and an infusion map, and combines the information in the maps to determine boundaries between finger positions. In an embodiment, movement of a particular digit on a handheld controller is identified through such boundary constraints. In an embodiment, movement of fingers about a handheld controller is efficiently modeled based on the boundary constraints.