Many VSL instruments have samples call ‘performance trills’. These are not recordings of entire trills, rather samples of fast transitions (often over some range greater than a whole tone) taken from recordings of trills, that are meant to be used when performing trills. These are the ideal samples for use with Dorico’s generated trills. However it seems as if there is no way to select the patch (trigger a switch/cc) for use when generating trills. It seems highly unlikely, whatever the library, that the patch chosen for ‘nat.’ is the best choice.
Is there a way to select which patch to use for generated trills?
There’s no officially sanctioned way to do this, but you should find that you can define an additional switch in your expression map that can trigger the appropriate program change or whatever else might be needed to switch to the performance trills; this will of course mean adding a (hidden) playing technique to the score at the start of the trill as well.