When this option is selected in the Mixing Preferences page, Pro Tools automatically thins the automation breakpoint data after each automation pass.In the default settings for new sessions, the Smooth and Thin Data After Pass option is selected, with the Degree of Thinning setting set to Some. In most cases, this setting yields optimum performance while providing an accurate reproduction of your automation moves.If you select None for the Degree of Thinning setting, Pro Tools writes the maximum possible number of breakpoints. You can still perform thinning at any time with the Thin Automation command. For more information on smoothing automation data, see Smoothing.