Origin 0:0



  • Hi,
    I am currently building CoreXY printer and I have problem with mesh bed leveling.
    I personaly like origin (0:0) to be at rear and left. My setup is:

    Endstops - Xmin, Ymin, Zmax (X left from fron view, Y rear)
    When I move X+ gantry moves right, Y+ to the front (so when the head is in most forward position X reads +250)

    OK my problem - after runing auto bed level, printer thinks that origin (point 0:0) is in forward left so bed compensation is inverted for Y axis.
    Is there any way to flip the Y axis and still maintain origin 0:0 at rear-left.
    Only solution I found was to set the Ymin to -250 but this will make origin 0:0 in front-left.

    Sorry for bothering, but you are my only hope :D.
    Thank you.



  • You're conflating the 0,0 origin with where the printer homes to. They don't have to be the same. 0,0 should be the front left as this matches a cartesian coordinate system and will make getting parts properly aligned and oriented on the build plate to match the slicer.

    The homing position is controlled by your homing files.

    There are other options, like making 0,0 the center of the bed. This makes it very easy to have the slicer and the build plate origin match up.

    See these links for more information:

    https://duet3d.dozuki.com/Wiki/Centering_the_bed_or_setting_the_bed_origin
    https://duet3d.dozuki.com/Wiki/ConfiguringRepRapFirmwareCartesianPrinter
    https://duet3d.dozuki.com/Wiki/ConfiguringRepRapFirmwareCoreXYPrinter
    https://drmrehorst.blogspot.com/2017/08/setting-up-3d-printers-origin.html
    https://drmrehorst.blogspot.com/2018/07/ummd-better-way-to-set-up-origin-and.html


  • administrators

    @cichaczech said in Origin 0:0:

    I personaly like origin (0:0) to be at rear and left. My setup is:
    Endstops - Xmin, Ymin, Zmax (X left from fron view, Y rear)
    When I move X+ gantry moves right, Y+ to the front (so when the head is in most forward position X reads +250)

    That will give you a left hand coordinate system, which means that your prints will come out mirrored. Viewed from above, the +Y direction should be 90 degrees anticlockwise from the +X direction.



  • @cichaczech said in Origin 0:0:

    When I move X+ gantry moves right, Y+ to the front (so when the head is in most forward position X reads +250)

    OK my problem - after runing auto bed level, printer thinks that origin (point 0:0) is in forward left so bed compensation is inverted for Y axis.

    These two seems to contradict in my mind? As the others have pointed out you really ought stick with the convention of origin at the front left, but you could easily have the machine home to Xmin:Ymax, which would be the rear left (if you have a endstop at Ymax?)

    However you probably need to invert your Y axis stepper motor direction so that Y decrease as it moves forward, and increase as it moves backwards, and set your Ymin to 0.

    (Just for completeness; it is possible to to get your origin to be at rear left, but you need to mess with your slicer setup to invert the axis there so your parts don't come out mirrored. But you really don't want to go down that route, not all slicers support it, and you can suddenly find yourself wanting to use a slicer that can't deal with it. Been there done that, Tiertime has their stuff all messed up like that.)



  • Wow, you are really the best 🙂 thank you.
    So for me is the best to stick with the conventional origin front-left, mainly for compatibility with slicers or some controlling softwares.
    The thing is that printer will be working with multiple tools. Some larger, some smaller, longer..... And the only point which will be unaffected with tool change is rear-left.
    I will change the config.g and home__.g
    Thanks again. 🙂


Log in to reply