Apparently this video shows how Glide works in Caustic:
Advanced Tutorial - Glide
First of all…
Using a piano roll sequencer/editor is pretty uncommon in modular. There are options in VCV Rack though, e.g. Squinky Labs Seq++
About Glide…
For glide in Caustic two (monophonic) notes must either be played consecutive or overlapping. The Glide time is the time between the end-of-note of the first note and the start of the second note.
Apparently, if there is no overlap between notes, the Glide time is ‘minimal’ (should be zero). Any overlap time will be added to the glide time (also unusual). Not sure about the modulation curve (linear/exponential).
In modular pitch/note (V/Oct) and note on/of (GATE) are controlled seperately.and live their seperate independent lives.
The equivalent of the MIDI note is the modular V/Oct. The equivalent of the MIDI piano roll note length is the modular GATE length. But using the GATE length to control Glide time is a bit of a challenge.
Using a slew limiter is generally the way to go to have gradual transitions from one value (in this case V/Oct) to another. But…for the per note variable Caustic kind of Glide you need control over the Glide time for each note (V/Oct). And as said, using GATE length for that would be a challenge.
One way to solve for per note varying Glide times (from zero to t) is simply using 1 sequencer(row/channel) for V/Oct (pitch/note) and a second sequencer(row/channel) to control the slew rate via CV.
You could use Befaco Slew Limiter (polyphonic) or similar. It offers control over slew rate via CV inputs for rise and fall. Also offers general and fixed control over the shape of the rise and fall slew curve (lin to exp).
But…you can also simply use a Sequencer that supports Glide/Slide, e.g. the Impromptu - Phrase Sequencer (16 or 32). But…no piano roll.
Or even have the synth included as well…
https://library.vcvrack.com/ImpromptuModular/Semi-ModularSynth
Here’s a demo/instruction video including Glide/Slide using Impromptu Phrase Seq by @Omri_Cohen
Let’s build the Roland TB-303 in VCV Rack - YouTube