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Posted (edited) · Merge Models not aligning, nor are model origins aligning

Good Afternoon I am struggling with a project to make a simple coaster wit a logo and name. I made the base in Solidworks then used a cavity to make the insert portion (which does not go all the way through. I have tried everything I can think of to align them and get them to merge properly in Cura (5.9.0). I even setup a new coordinate system at the very top point of the S on both models and made sure that was selected as the reference output when exporting. I have uploaded a picture of what the part looks like in Cura when I try to merge them, as well as when I have them both aligned at X0 Y0. 

 

Any help would be appreciated. I don't see any option to align origins and honestly I am not sure why the origins weren't already aligned. 

 

edit: Checking in meshmixer you can see that the origins are aligned properly so it has to be an issue in Cura not the file solidworks is outputting.

 

merge models failure 2 .png

merge models failure.png

Take 3 leaving coaster base.STL Take 3 leaving coaster text.STL

base origin correct.png

text origin correct.png

Edited by DAYochelson
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    Posted · Merge Models not aligning, nor are model origins aligning

    I might have a solution, what I do in the software Blender is to press the . Button after selecting the model and choose ‘bounding box center’ from the pop-up panel. Then you go into object > origin > origin to geometry.

     

    the issue is that to align the models, their respective origins must align between Cura and your CAD software. Cura used the bounding box center. 
     

    Hope you are able to proceed!

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    Posted · Merge Models not aligning, nor are model origins aligning

    The problem is that the centre of the text model is offset from the centre of the base model, and Cura sets position by the centre of an object (on the X and Y axes), not a corner:
    image.thumb.png.bbededb9e0fd14cd27ca008c01442b13.png

    In order for it to line up when you import both and set their position to the centre, both X distances need to be the same and both Y distances distances need to be the same.

     

    To make them line up, for each axis you need to subtract the smaller gap from the larger one, divide it by 2 and then move it that far in the appropriate direction.

    i.e. for the X axis here (9.82 - 7) ÷ 2 = 1.4mm to the right.

    and for Y axis (16.68 - 11.38) ÷ 2 = 2.65mm down (from this perspective)

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    Posted · Merge Models not aligning, nor are model origins aligning
    19 hours ago, DAYochelson said:

    edit: Checking in meshmixer you can see that the origins are aligned properly so it has to be an issue in Cura not the file solidworks is outputting.

    Actually, when I load both STL files you provided in your post into meshmixer I see that they have non-matching origins (that match with what Cura does when merging). Something may have happened when you exported the stl files.

     

    image.thumb.png.f104458e8caf1baa346838143c85b349.pngimage.thumb.png.0a700e022332f573d2a3fd983256daac.png

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    Posted · Merge Models not aligning, nor are model origins aligning
    1 hour ago, Slashee_the_Cow said:

    The problem is that the centre of the text model is offset from the centre of the base model, and Cura sets position by the centre of an object (on the X and Y axes), not a corner:
     

    In order for it to line up when you import both and set their position to the centre, both X distances need to be the same and both Y distances distances need to be the same.

     

    I am sorry, this is nonsense.

     

    When loading a model, Cura places it in the center of the buildplate. It never shows the original origin of the model, but it does remember it. If you load two STL files of models that share their origins, you can line them up perfectly by using the "Merge" functionality in Cura, no matter what proportions the STL models have.

     

    It just so happens that the two STL files used by OP are not aligned by their origin (even though OP seems to be convinced that they are).

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    Posted · Merge Models not aligning, nor are model origins aligning
    18 minutes ago, ahoeben said:

    I am sorry, this is nonsense.

    I was talking about getting them to line up in Cura, not to use the merge tool specifically, as per the OP's conundrum:

    19 hours ago, DAYochelson said:

    I have tried everything I can think of to align them

    99% of the time just getting them to line up in Cura is what people want, especially if they have dual extruder printers, which makes merging not an option.

    (n.b. I'm well aware I can't know whether the OP has a dual extruder printer. But making models separate like this instead of just extruding the features from the main body is how you'd do it for one.)

     

    21 minutes ago, ahoeben said:

    It just so happens that the two STL files used by OP are not aligned by their origin (even though OP seems to be convinced that they are).

    That one I certainly won't argue against.

    image.thumb.png.11956c6439bff261eeb39301aa8753e4.png

    Origin: bottom left corner at world origin.

    image.thumb.png.cfb0e852c617bf2ecbe51189e96692e3.png

    Origin: ~10mm left and ~27mm backward from world origin. Not taking into account that it has to be inset from the origin in order to line up.

     

    Result: By Cura placing models at the centre of their X and Y dimensions - the models themselves, not taking the model's origins into account - the difference appears much less than it actually is.

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    Posted · Merge Models not aligning, nor are model origins aligning

    My older CAD software won't add any location data to an STL.  All my STL files come into Cura at their Center of Geometry (the mid-point of the bounding box of the model).  Cura is not an "Assembly Modeler" so getting things to line up can be a head scratcher.

     

    My workaround is to mount the models (in their correct respective locations) to identical plates that extend beyond the extents of the largest model, and are 1mm thick.  When the "Unioned" models are brought into Cura they get located at X0, Y0, Z= -1.  The plates don't print because they are below the build plate but they locate correctly because they are all the same size.

     

    The main model here is irregular and the other models must fit exactly into the holes.  All the plates (there was actually only one) are 5mm smaller than my build plate and are located at Z= -1 because they are 1mm thick.

    image.thumb.png.88130b0cc5c640456993da4b53573eda.png

     

    When all the models are re-located to X0 Y0 (or "Merged" and moved) the small models fit exactly into the holes because the rectangles determine the Center of Geometry of each separate model.  They are geometrically identical in the X and Y.

    If there had been different Z locations for the different models, then I would have taken care of that in the "Union" in CAD.

    image.thumb.png.4e8c38ab2e486af54efa46d3a5311e69.png

     

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    Posted · Merge Models not aligning, nor are model origins aligning
    22 hours ago, Slashee_the_Cow said:

    I was talking about getting them to line up in Cura, not to use the merge tool specifically, as per the OP's conundrum:

    99% of the time just getting them to line up in Cura is what people want, especially if they have dual extruder printers, which makes merging not an option.

    (n.b. I'm well aware I can't know whether the OP has a dual extruder printer. But making models separate like this instead of just extruding the features from the main body is how you'd do it for one.)

     

    That one I certainly won't argue against.

    image.thumb.png.11956c6439bff261eeb39301aa8753e4.png

    Origin: bottom left corner at world origin.

    image.thumb.png.cfb0e852c617bf2ecbe51189e96692e3.png

    Origin: ~10mm left and ~27mm backward from world origin. Not taking into account that it has to be inset from the origin in order to line up.

     

    Result: By Cura placing models at the centre of their X and Y dimensions - the models themselves, not taking the model's origins into account - the difference appears much less than it actually is.

    I do have a dual extruder Ultimaker S5 I loaded black Tough PLA into Extruder 1 and White Tough PLA into extruder 2. what I finally did to get them aligned was make the "Text" have a circular border 0.4mm larger than the base so there geometric centers would be the same. not my ideal solution but it ended up not mattering because I have to now spend more time aligning my printheads and will do that after the weekend.

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    Posted · Merge Models not aligning, nor are model origins aligning

    "...so there(sic) geometric centers would be the same."

    Yes.  Not ideal as it does involve more effort.  That method does have the advantage that it always works.

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