The design process of any kind of gearing is a complex multi-step procedure; and different directions of the design and choice of parameters are possible with respect to many factors: initial requirements to the gear under design, mode of its operation, the applied
technique, specific decisions made by a designer, and others.
The determinacy level of the design procedure depends on the accumulated experience of design, manufacture and application of gears,
formalized as standards for the calculation and CAD systems.
Note that the design procedure is not quite determinate even for the most widespread cylindrical gear with its national and international standards and plenty of various computer systems, since there are (and obviously, there will be) many unsolved questions related with the strength evaluation,wear resistance, vibration activity, thermal balance, different degrees of manufacturing accuracy, materials of links, lubricants, modes of loading and so on.