They are all types of phase distortion. If you think of waveforms as arrays of amplitude values, normally you play through each sample/value in the waveform in equal amount of time, or linearly, at the speed set by the oscillator frequency. If you look at this lookup function as samples/time, it corresponds to a ramp up/sawtooth. But if you "bend" that linear function / sawtooth in different ways, which means spending more time in some parts of the waveform than in others you get phase distortion. One fun thing to do in phase modulation synthesizers that don't have built-in controls for phase distortion is to stop the "carrier" sawtooth by phase modulating with the reverse of the carrier saw at the same frequency, so that you get silence. But then you can start modulating the modulator again to get PD'ish effects.

@@Tsarpf Oh wow ok, that makes a lot of sense: From what you describe, I'm imagining the line of whatever waveform representing a series of connected dots that would play through steadily frame by frame while un-warped. With sample-position or frame at x-axis and time on y-axis, plotting this would result in a straight ramp up shape as you say. And if i'm understanding you correctly, these warp modes are different ways this curve is modified. That's an awesome explanation and thank you so much for taking the time to explain this to me. Clears up so much mystery. In the second half of your comment: do you mean having 2 identical waveforms exactly 180 degrees out of phase with one another to produce total cancellation and then playing with the phase position of one of them with an LFO or envelope? If so, ill definitely try that out some time. Again, thanks for your response!

Click on the point again: a circle will make curved lines, and a diamond will make straight lines.

google it

The different ways the current wave cycle can be messed with, which Serum, Massive, and Vital are able to do by default