Abstract: A spray coating simulation for a robotic spray gun assembly imports a discretized model of an object geometry. Next, the simulator imports a numerically characterized spray pattern file and a robot motion file having a plurality of motion positions, dwell times and orientations defining a motion path of the spray gun. The individual motion positions within the motion file are read and a determination is made as to which portions of the object geometry are visible at each motion position. Next, a coating thickness at each visible portion of the object geometry is computed, based on the specified spray pattern data, the dwell time and the orientation of the robot motion path, for each motion position. Finally, the total coating thickness over the object geometry is calculated.