calculated see fig1 c again transformation matrices from cone to bit coordinates are calculated step 128 and the number of bit revolutions and maximum time steps delta are input step 130 the cones are then counted step 132 the bit and cone rotation angles are calculated at the given time step step 134 and the rows are counted step 136 next the 3d tooth surface matrices for the teeth on a given row are calculated step 138 the teeth are then counted step 140 and the 3d position of the tooth on the hole bottom is calculated at the given time interval step 142 if a tooth is not cutting counting continues until a cutting tooth is reached step 144 the cutting depth area volume and forces for each tooth are calculated and the hole bottom model is updated based on the crater model for the type of rock being drilled next the number of teeth cutting at any given time step is counted the tooth force is projected into cone and bit coordinates yielding the total cone and bit forces and moments finally the specific energy of the bit is calculated step 146 finally all results are outputted step 148 the process can then be reiterated if needed four coordinate systems are used in the presently preferred embodiment to define the crest point of a tooth in three dimensional space all the coordinate system obey the u201c right.