MaxMSP patch as Midi Controller in Ableton

As far as I remember, Control Surfaces need to have a definition
to function as such.

Thank you for your reply. Anyone else who might have some thoughts on this?

you probably don't need IAC at all(it's overcomplicating things... Tom likely incorporates that in order to leave it as generally open, to all DAWs on all operating systems, as possible...)
...try simply choosing 'from Max 1'(or similar) for MIDI input/output port, first... that can often be the swiftest/easiest way(fall back on IAC only if the direct Max-related MIDI ports don't work on your system). here's a video that explains MIDI to Ableton directly:

Hi 👽R∆J∆ THE RESIDENT ∆LIEN👽 thank you so much for this video! That is exactly what I was looking for. I have just tested it with another patch of mine and it works perfectly. Unfortunately, it doesn't work with the patch from Tom :/. Somehow I am not able to map the data coming from the OSC route. Am I missing something? Is there a trick? Thank you!

happy to help :)
the rest should be as simple as setting the main 'MIDI OUT' menu to 'from Max 1' (or 'from Max 2'.. whichever port you choose to use in Ableton), from there it sends that through 's mididevice' to alter the port for all the 'ctlout' objects in the patch at once:

...
HA! NO!
i'm wrong...
now that i look through it, it seems Tom didn't set the proper messaging to route the appropriate port...
i think you need to add this:

by the way, in case you haven't run into these shortcuts yet, to make this easy, create the 'port $1' message first, then hold down 'option'(or 'alt' on windows), while dragging across the patch-cables right below the 'r mididevice' object so that they're selected all together, then you can just grab the green-nodes/handles and move them from one place to another:

then, connect the 'r mididevice' object to the inlet of the 'port $1' message and that should do it.
apologies if you already knew how to do the multiple-patch-chord selection... just making sure to spare you any tedium :)

with that in place, you should be able to select 'from Max 1' from the menu i was referring to at first, and you can then verify that it changed all the 'ctlout' objects to that same MIDI port by double-click-and-holding on one of the ctlout objects to see its pop-up routing menu will now show 'from Max 1' as well:

i'm pretty sure that should work for you (but i don't have Ableton and i haven't actually downloaded the 'OSC-route' objects yet to confirm the full functionality of this particular patch, so if that still doesn't work, i'd recommend trying to ask Tom or asking around on the Max Discord server... he's there sometimes... here's a server invite in case you need: https://discord.gg/jtQNTGaN)
[edit: looking even more closely... i don't think the 'r mididevice' routing is connected properly to all the 'ctlout' objects... but the jist overall is to make sure all the 'ctlout' objects in the patch, send via 'from Max 1'(or the other port), to Ableton... once you have the 'ctlout' objects sending properly it should be good to go]
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midi objects don't need port $1
port name alone is enough.

IAC buss is a better choice simply because it exists
no matter which app started first, multiple max apps, standalones,
Live, or any other DAW.
but this here is NO GO with midi objects !!!!

scale 0. 0. 0 127 , look at few output examples

you don't send that to midi objects !

Hey you two, thank you both for your answers. I really appreciate your time. I think the problem lies in how the data can be mapped, because if I rebuild the path from the video above 👽R∆J∆ THE RESIDENT ∆LIEN👽 it seems to work, but because I can easily map the slide object. With the data coming from the OSC-route I can't map it. I have tried to let the data control a slide object, but that's also not possible. I don't know SOURCE AUDIO if that is what you mean with "you don't send that to midi objects!". Do you maybe have an idea on how I could use that data for mapping? Otherwise I will check out the discord channel as suggested by 👽R∆J∆ THE RESIDENT ∆LIEN👽. Again, thank you very much.

If you leave that scale objects in there and they output
illegal values (out of 0 - 127 range), you will have no midi output
that can be recognised by Live and so assign any mappings.
In worst case it might tilt IAC buss.

before going into complications, insert clip 0 127
between one scale output and ctlout, to see if that helps.

you could also replace scale with zmap, because it clips
values out of set range.

Bad in that patch is also that output range objects are not set to min max range of 0 - 127, look at this here:

very sluggish patch alltogether