@oliof here are some pictures and videos on google drive. Google you probably have 
https://drive.google.com/drive/folders/17GNqAortkIXxc3fdv3P3tbFUaRGGbXFE
and this is somewhat more ambitious build, quad markforged mockup XY plane, but awesome life happened to me so making it proper and metal is on hold:
https://www.youtube.com/watch?v=dbukhT5yJ8k
@dc42 This is an update to an old topic. I have waited very, very long to get the multiplexer chips on breakout boards. So, yeah, a delay.
But, just want to report that i have success with multiplexing only enable pin. External drivers are daisychained for step and dir and En is muxed.
Mux is controlled with 100-103 GPIOs.
And it works! Such a cool little thing this mux modules.
Hello,
is it possible to do meshbed compensation not by the means of Z axis but with using a separate mechanism incorporated? Or is meshbed compensation bound to be done through/with Z axis ? @dc42 @jay_s_uk anyone? 
and if possible, is it doable for like an IDEX machines, while printing ditto job, that each head would individually actively compensate. Especially now that multistream gcode capability is becoming a real thing (respect on that achievement btw)
thank you
@oliof thanks .
Wont lie: A lot of thinking went into concepting and construction on both of those.
Hi all.
I have rewired everything. That was it. I had 105% belief in Duet that itâs not faulty. I do hope it fixed the issue for good and i think i know exact reason: me not puting everithing on a mount and due to using breakout boards not being fixed and cables constantly moved all over during âmakeoverâ, it left those little hairs doing nasty business to thermistor cable (and maybe other places).
Everything looked ok for a freshly assembled proto-mod of chinese base machine, yet it is/was everything but a nice and tidy thing. The box is printing
As i redid the crimping, & replaced AC power switch, all is fine. I didnât suspect the breakup board of vga cables to printheads early on..
How does it come to a state, when you can make testing, heating, moving etc, but it fails to operate on gcode?
And coincidentaly, couldnt it be a sort of check-up test?
i edited/deleted because i thought you won't get it
i'll call my coding brain friend and will share if anything comes out of this.
Thank you for a very constructive debate.
@Phaedrux as promissed, the pictures of a build in progress
https://ibb.co/9qDPTWn
https://ibb.co/CsGbTPb
https://ibb.co/6b5DQxL
It got pretty compact.
Needs a lot of work still to get the flat round cabling routed to both sides of X gantries from the bottom, then flat cables from there to each head, make breakout boards on toolheads for ribbon cables etc.
But all in all. There is progress
RESOLVED
For anyone, that might experience such headache and stumbles upon this:
one maps the axes, not the motors to the tools. and you count the axes, not specify motors...
@droftarts i did not understand what you meant that first time. Now i get it.
Thank you.
@dc42 & @Phaedrux : issue has been resolved. One maps the axes not the motors. I get it now.
@gringo you set the tool 0, tool 1 and tool 2. Tool 2 is having components from tool 0 and 1.
You set the origin to bed center.
And you only set one piece in your slicer. The machine will print it with both heads.
Should you print mirrored, youâll just control that in the slicer.
What kind of printer are you using? If itâs i3 design, and running Duet, i have such and have a repository to share for you to build on. I use Tenlog D3 base, design evolved but IDEX stuff is still there in shared map.
There also is an S3d profile..
Anyhow, if people here donât mind, repo si here:
https://drive.google.com/drive/folders/14S6cTYI0-bUS4PPHw44QKlxj1BM217J-
And facebook group with a bunch of people is here:
https://www.facebook.com/groups/237163797566846/
@wdenker i donât think that is how it works... unless you want to do parallel printing, but that adds a whole new level of complexity to the slicer side, daisychaining control boards via SBC, probably syncing Z, or go with Autodesk project Escher kind of way... complicated stuff..
As current setups go, you do mirror or duplication, and while it looks individual, it really isnât. Without a user error, they will not collide.
If youâd like to just add redundancy and eliminate the potential user slicing error, you could put an extra endstop (preferently optical) on one of the gantries and before they collide, they stop.
@kru96 when selecting T2 you are selecting ditto tool (t0 is left probably, t1 is right and T2 is both...)
They move each on aproximate center of their bedhalves because in Tool definition you are setting the offsets and that positions them accordingly.
The bed center is in the middle of the bed for ditto/mirror mode to function.