Awesome model, thanks for contributing this! I made a few minor changes that I can share. Primarily I needed to thicken the slide pipes and decided to make the pipes on the upper valve case separate so I could get a better surface finish when printing them (pipes I print along Z, valve case I print upside down). I haven't been able to produce much by way of sounds yet, but since I'm not a Trumpet player who knows (though I did sit next to them in HS band ;) ). Will try a different mouth piece and advise.