In this segment from Bitwig's Modular Concepts series, the host reframes what a low-pass filter actually does: rather than simply cutting frequencies, it rounds off abrupt signal transitions, slowing down how fast a signal can change. Lowering the cutoff on a square wave gradually morphs it toward a sine wave, which makes the underlying math visible.
From there, the bit applies that logic to pitch control. By routing the pitch input through a low-pass filter before it reaches the oscillator, abrupt note-to-note jumps become gradual glides, producing a musical portamento without a dedicated lag module.
The host acknowledges that a lag module does the same job more intuitively, with timing set in musical terms. But the point is that understanding what a filter is fundamentally doing opens up uses well beyond tone shaping, and that kind of cross-functional thinking applies to any modular environment.