A method of operating a robotic system to efficiently remove material from a workpiece based on a density distribution of the material of the workpiece. The density distribution of the material of the workpiece is determined from a three-dimensional representation and evaluated by classifying the plurality of points or voxels into a first density classification and a second density classification. A navigation computer generates a first tool path and a second tool path for the tool based on the evaluated density distribution. The first tool path is associated with the first density classification, and the second tool path is associated with the second density classification. The position of the tool relative to the workpiece is tracked with a navigation computer and controlled with a manipulator controller based on the generated tool path to remove material along the first tool path, and remove material along the second tool path.