This Bitwig Studio tutorial from the official Bitwig channel walks through the Gain expression editor inside the Detail Editor Panel, showing how to draw and adjust volume automation directly on individual audio events. Because Gain, Pan, Pitch, and Formant expressions all share the same editing workflow, everything covered here transfers directly to the others.
The freehand pen tool lets you draw continuous curves across an event, while holding Alt or Option switches to a stepped drawing mode, useful for hard-cut volume jumps or rhythmic panning effects. The default step size is 16th notes, but changing the grid resolution at the bottom of the panel snaps steps to any value you need, like quarter notes.
For smoother transitions, clicking between two existing points while holding Alt or Option creates bezier curves, giving you control over the shape of the fade rather than just its endpoints. Once points are placed, you can select multiple at once and move them together, both horizontally and vertically, without disturbing the rest of the automation.
A less obvious feature: selecting any individual point opens its properties in the inspector, where you can type in an exact position and value. When freehand drawing makes it hard to land precisely where you need, this is the fastest way to lock things in.