5D Touch refers to ROLI's 5 dimensions of touch. The dimensions of touch describe the ways that you interact with a physical surface when you play an instrument.
The dimensions are called Strike, Press, Glide, Slide, and Lift.
Strike corresponds to the MIDI message of note-on velocity, Press to aftertouch or pressure, Glide to pitch bend, Slide to CC 74, and Lift to note-off (release) velocity.
Strike describes the force with which a finger makes contact with a keywave. Strike corresponds to velocity on a standard MIDI controller and can be assigned to affect many parameters in Equator and third-party instruments.
Press describes the pressure applied to the keywave after it is struck. Press corresponds to the MIDI control message of "aftertouch" (or "pressure"). The Seaboard and Lightpad Block register each moment of continuous touch, transmitting minute variations of pressure. This allows for detailed expressions such as swells and fades from the initial Strike until the final Lift. The measurement is polyphonic and can be assigned to many synth parameters in Equator or other third-party instruments. For example, Press could increase the amplitude of the oscillator or the speed of the LFO. In Expression mode, the RISE's right Touch Fader adjusts how sensitive the playing surface is and so how intensely it responds to pressure.
Glide describes horizontal movements from side to side on a keywave or along the ribbons. Glide movements bend and adjust pitch as naturally as on a string instrument, allowing effects such as vibrato and glissando, all on a polyphonic basis. Glide is transmitted as MIDI pitch bend and can be assigned to many different parameters but is typically assigned to pitch. In Expression mode, the RISE’s left Touch Fader allows you to shift between two extremes of Glide behavior, with a piano-type response at the bottom, and a full Seaboard response – complete with intuitive pitch bends and vibratos – at the top.
Slide describes vertical movements up and down a keywave. Slide can be assigned to most sound parameters in Equator. An upward movement along the top of the keywave, for example, might open a filter that transforms an acoustic guitar sound to a bass guitar sound, while a downward movement will close that filter. By default, Slide is transmitted as MIDI CC 74. In Expression mode, the RISE's central Touch Fader allows you to adjust the behavior of the Slide dimension of touch, making it so that your fingers would need to move a smaller or larger distance along the keywave to have an effect.
Lift describes the release velocity or speed of liftoff from a keywave. Lift can be assigned to most sound parameters in Equator. For example, a rapid lift can result in a lingering resonance or a hard pluck. Lift is transmitted as MIDI release velocity which some third-party instruments can also respond to.
For more details on the five dimensions of touch, check out Course: Five Dimensions of Touch by Erin Barra on the Learning Hub.