Currently, gliss playback is limited to stepping by semitones. However, I have found a way to smooth things out, depending on your sample library.
Create a Playing Technique that triggers the Playback Technique “Glissando Up” and “Glissando Down”.
In your Expression Map, create a Base for Glissando Up / Down. Add CC20 (Portamento), with some suitable value. 80 worked for me. (You may need to turn on Legato controls, too.)
Then use an actual gliss in conjunction with your Playing Technique. It’s a shame that the gliss doesn’t trigger the PTs by default. You can of course hide the Technique mark.
You’ll need another thing in the Ex Map to turn it off. Possibly Add CC20 : 0 to the Natural Base.
Depending on the instrument type and sample quality, the results may vary from risible to accurate.
Can you get enough pitch bend for the octave you have above? I haven’t used it for this purpose (interesting trick that) but usually it’s -5/+5
What about using sampled glissando? I should check, my libraries should include that in an effects sample I’d think. Instrument specific obviously, trombones being the best.
there’s a legato+portamento instrument in Halion but I see no evidence that there is a specific portamento technique, nor any evidence of one in the Expression Maps entries. Portamento is supported on a sample level by all the more advanced libraries. The method varies from specific keyswitches to velocity level and no doubt others though I can’t think of any which are controlled through CC20 (which isn’t to say there aren’t any!).
Glissando as a pure slide rather than the sort of swoop of a string portamento isn’t yet supported in Dorico but it’s certainly on their list!
I’m glad I found this post—very cool trick! I’m wondering, for long glisses over small intervals, I guess you just have to adjust the portamento time (i.e., set it to loooong), yes?