Two inflection-point sliders are provided on the site, one adjusting the vertical position of the inflection point and the other its horizontal position. These sliders are given values which represent the fractional position of the point relative to the cup shape. Thus, a setting of 0.5 on the vertical inflection point means that it is located halfway down the cup, midway between the rim and the point where the throat meets the backbore. Thus, when the setting of vertical inflection point is increased, there is more of the cup above the inflection point, making it more cup shaped. The horizontal inflection point is similarly set between the rim inner diameter and the throat diameter. When the horizontal inflection point is increased, the cup is widened generally. The settings are shown on the figure below:

Changing the position of the inflection point on a mouthpiece has a considerable impact on the cup shape and the two sliders which are provided to allow changes to this are limited so as to avoid really impossible forms. On Trumpets, for example, the vertical settings vary from 0.2 to 0.6 while the horizontal ones range from 0.2 to 0.5. The diagram below shows the effect of resetting the vertical and horizontal inflection point settings to their maximum and minimum values.

You may investigate the operation of the two inflection point settings in the diagram below.

<div class="odoko-diagram-sliders">
  <div id="sliders-simple-inflection_point_vertical_fraction-inflection_point_horizontal_fraction-cup" data-params="inflection_point_vertical_fraction,inflection_point_horizontal_fraction">
  </div>
</div>