[virtualritz]

This partly happened in tango in the 90's, when Gustavo Naveira, Chicho Frumboli and Fabian Salas came together to create a structural and kinesiologica base for something that previously existed more as "an intuition".

For each basic configuration of leader and follower and their bodies they looked at all permutations.

Then they constrained it first to the subset of those that are possible to do at all, kinesiologically.

Then further to the subset of those that could be danced with reasonable comfort.

And finally the subset of those that are easy enough to be taught to students and would work on a crowded social dancefloor.

None of this was done with the help of computers.

The most systemic documentation of this is possibly Mauricio Castro's book "Tango -- the structure of the dance".

But lately a lot of new books were published on tango technique; I may be out of the loop.

A friend of mine who's also a tango professional is currently looking into the feasibility of doing a PhD thesis on this topic.

He wants to use ML to spit spit out the full motion tree of tango.

Both to be able to document it automatically, i.e. using generated 3D animations, as well as to discover new combinations the manual approach used by Naveira, Frumboli and Salas, over a quarter century ago, will have missed.

[cryptonector]

As a one-time avid Tango dancer, while I believe all the motions/steps can (and have been) be sketched out, named, and notated and put to paper, that which can be written down is necessarily insufficient to make it easy for people who understand the syntax but not the dance to replicate the dance easily. Let alone beginners. There's a great deal of unspoken communication in the embrace, in the way the partners' center of gravity is shifted about, in the music and song, in the timing, in their understanding of each other's abilities, and in their personal connection. Those details would have to be rediscovered by those reading the notation.

Some things are just hard to write down with fidelity. Think of tastes: we can have cookbooks, but its hard to reproduce the exact ingredients of grandma's cooking, or that one restaurant. Smells are even harder to express in words. Dance is kinda like that.

None of which is to say that one shouldn't do it, or try. Quite the contrary. It's a good challenge! Even if you could write it all down, leaving a bit of mystery/mystique would be a good idea, but I don't fear that mystique will be lost.

[virtualritz]

> As a one-time avid Tango dancer, while I believe all the motions/steps can (and have been) be sketched out, named, and notated and put to paper, [...]

This is obviously untrue. For simple math reasons.

If you believe that, I suggest reading an intro to combinatorics.

Or just doing the math in your head for a combination of two steps. Leader does forward step towards follower's forward cross.

Just in one system (cross or parallel) and considering how deep the step is (outside, sacada, deep sacada/behind/in front) and where the leader steps (behind free foot, next to outside, next to inside, in the middle between legs, next to to standing foot inside, next to outside, in front), we can reasonably say we have 21 possibilities. Now multiply by system and that's 42. Now multiply by combinations of systems on one side and that's 84. This still makes a lot of simplifications but we're talking one step. Furthermore, if we mirror, we can't just assume the same observations apply, as tango has an open and closed side, etc. etc.

The endeavor is also not about capturing the essence of a dance but about exploring a motion space; structurally and kinesiologically.

Tango, specifically, will elude documenting on so many levels, otherwise, it's not even worth talking about.

[fzeindl]

I have had the same idea about martial arts. Not sure it is possible. In dancing you have at least some symmetric patterns and rhythm, in martial arts you have even more stances, rotation around more axes and arrhythmic moves.

good dancing like good fighting isn‘t mechanical either, it is good because it relies on little imperfections. Just like MIDI files cannot replace a concert pianist.

In the end I think motion capture of extremities along with some easing of paths and compression of point-clouds (think bezier curves) might be more worthwhile than a notation.

[knuckleheads]

Somebody sort of did something like this, not exactly the same, but I think'll get a kick out of it. I don't do martial arts but as part of the research I looked into how people represent martial arts in written or abstracted form. During this time, late one night, I found this website: http://eel.is/GrappleMap/index.html It turns out one guy made a website that let you simulate a ton of BJJ moves and sequences, designing an abstract BJJ representation as well as making a 3d animator/viewer for those animations http://eel.is/GrappleMap/composer/index.html?484,517,518,125... It's all up on github https://github.com/Eelis/GrappleMap/ and some sample videos can be seen here https://www.youtube.com/watch?v=rC7zTBMPj1Y https://www.youtube.com/watch?v=MAeBgGZ1GdM http://eel.is/GrappleMap/index.html I spent hours messing around with this, he got it working in VR too. More or less one guy just writing a ton of C++ on his own to make something incredible. https://github.com/Eelis/GrappleMap/graphs/contributors

[viraptor]

> in martial arts you have even more stances, rotation around more axes and arrhythmic moves.

I wonder how true this is. Specifically I think you could simplify the moves into steps with "who hits who" states. You could normalise out the rhythm, following the "everything's in 4/4 if you don't count like a nerd" idea.

So you'd end up with just the key frames of either contacts/impact or change of the movement direction. Would martial arts really have even more variety here?

[fzeindl]

> Would martial arts really have even more variety here?

It depends, but yes. Martial arts is not just boxing. Take the following choreography from one style of Pencak silat:

https://youtu.be/8H0x1AKlpM4?si=QJLNffTUozn9kCf9

[viraptor]

I'm experienced with both sides here. I think they're fairly comparable in moves/complexity if you include the non-partnered dances in general.

[hobs]

Time to load up toribash

[knuckleheads]

That's super helpful thank you for writing it all out! I bought Castro's book, looking forward to reading it more. If you have any other resources/recommendations like this I would love to see them. I had tried TANGOBOOK: Dance Notation of The Classic Tango by Hsieh, Felipe and found it to not be all that helpful to me as a beginner Tango dancer. I feel like the footwork diagrams left out a lot of where I was supposed to be pointing to with my chest, but I'm not very good at Tango, so it's hard for me to say that that actually matters.