Tokøta from Mastering.com breaks down the shaping options inside Logic Pro's Arpeggiator, showing how a few simple parameters turn a mechanical pattern into something that actually breathes.
Note length controls sustain: pull it down for a choppy, staccato arpeggio, push it up toward 150% for notes that blend together, or randomize it for organic variation.
Velocity can follow what you've drawn into the grid, get locked to a fixed value from 1 to 127 for consistent punch, or randomized for a looser feel.
Built-in crescendo and decrescendo let a run swell from soft to loud (or back down) across each phrase, which only reads clearly when every note starts at the same velocity.