When toolpaths are generated, the estimated horsepower required for each operation is calculated by using the depth of cut, width of cut, feedrate and stock material. The actual shape of the feature is not taken into account. Instead just a simple straight cut is assumed when calculating the estimated horsepower. This number is reported in the Operations list of the Details tab as the Est HP. The estimated horsepower is only calculated for operations that are cut with flat bottom tools with a fixed depth. This includes 2.5D milling features, and 3D Z level roughing and other 3D features with Z increment set.