This walkthrough from Mastering.com covers Alchemy's MSEG (multi-stage envelope generator), a tool for building envelopes far more complex than a standard LFO or envelope allows. You can add points by right-clicking, drag them into custom shapes, and loop individual segments within the envelope.
Four loop modes change how that shape repeats: none, continuous, sustain, and forward/backward, which reverses direction each cycle for a genuinely different kind of movement.
Slide and stretch let you reshape the envelope's timing itself. Sliding shifts segments across the timeline, while stretching compresses or expands them so a section speeds up or slows down without redrawing it.
Together these controls turn the MSEG into a shortcut for rhythmic, evolving modulation. Presets and randomization are good starting points for getting familiar with how the shapes translate into sound.