OK...go here: https://www.flickr.com/photos/8429881@N06/sets/72157602899680757/
What you're looking at is a collaboration between Bob Moog and the composer Joel Chadabe that was installed at SUNY Albany back in 1969. This was known as the "Coordinated Electronic Music System" or CEMS, and was the first modular rig specifically intended to do what we now call "generative music". Chadabe's "Ideas of Movement at Bolton Landing" was one of the first such works that explored this process, and you can hear that here: https://joelchadabe.net/ideasofmovement/
Now, for those trying to build a proper generative rig...pay very close attention to those pictures of the CEMS. Yes, those ARE eight Moog 960 sequencers. Yes, that IS a custom triggering/timing system at the top of one rack. And so on...
"Ideas of Motion..." actually sounds rather simplistic when compared to present-day generative work. And that's because it is. Even with this large Moog rig, you don't get too much going on.
So...if the result from this monster system is actually as simplistic at it sounds, what's actually going on here?
Well...like many generative builds, there are a lot of modulation sources here, notably in the form of those eight Moog 960s that also control pitches and the usual sequenced stuff. But the sound generation aspect is pretty simple, which is typical for that time period; it would be another year or two before Dr. Tomita started showing everyone how to do really nuanced sound on the Moog. And as we know, nuance needs more of...everything, tbh.
So, sure...Eurorack makes things physically smaller. But not functionally. Not even close. To get Chadabe's results in "Ideas of Motion...", you still need much of what you see in those pics of the CEMS, or similar. Then, to get that ambient sonic complexity, you need the nuance of later synthesists...so, let's see what Tomita was up to in the mid-1970s: http://www.isaotomita.net/interviews/KEYBaug1977/images/1.jpg
Oh...snap.
Even if you shrunk all of what you see in that pic down to Eurorack dimensions, you would STILL have something pretty damned big. I mean...that's a IIIp, a 55, and there's even more that's not in the frame. Slap THAT together with the CEMS's control systems, though, and you'd have a top-shelf generative ambient rig. But the problem is that you'd really need to be working on that scale to get something that's musically effective. True, we have denser functionality on modules these days, and everything's smaller and so on, but you'd still probably be talking about a rig that would take up a whole Doepfer A-100 12U Monster Case at minimum.
Now, hopefully this explains why some of us keep saying that you can't do a proper, musically-interesting ambient generative setup in a two-row 84 hp cab. Even if you could jam a lot of the "voicing" in with 4 hp and smaller modules, you would still have issues with supplying enough integrated timing/sequencing/modulation sources to make it do something interesting. Hopefully this explanation is helpful to those of you contemplating this concept. Note that I'm not saying "don't do this"...instead, if you're going to do this, look at this as an example of how TO do it, understand the scale you'd be working on, and THEN start working out ideas. Anything too much smaller isn't going to work as well as you'd think.