What Is a Important Parameter When Two Different Diameter Gears Need to Mesh Properly? Meridian > Gear Knowledge > The start step of mechanism blueprint using gears > Know near parameters that determine gear shapes Understanding various technical terms is essential in designing gears. In this affiliate, we explicate the terms and their meanings of gear parameters. ane. Gear shapes In full general, tooth profiles with anfractuous curves are used for shaping gears. (Figure 4-1) "Involute curve" is the bend fatigued by the terminate of the thread which is beingness unwound from a cylinder under tension.