Jump to content

Unwanted top layer - or: how to use horizontal layers inside model without a final top layer


Recommended Posts

Posted (edited) · Unwanted top layer - or: how to use horizontal layers inside model without a final top layer

Hi,

 

i have a big problem printing some STLs. The STLs are open on bottom and top. However, when i enable the top/bottom layers in cura, cura closes the bottoms and tops.

If i disable bottom/top layers by setting them to 0, cura also does not print some horizontal parts inside the model that should be there.

 

This is my test-part: https://www.thingiverse.com/thing:2115282/#files

Cura 3.1 is used.

 

I made some screenshots:

1: In solid view you can see the horizontal part in the blue circle.

2: with top-layers enabled, the model is closed on top (but should be open)

3: inside the model now looks good

4: without top layers the part is missing

 

So it seems that either i can

a) have the model open but parts missing

b) have the model closed but inside its OK

:-(

 

I already tried the "cut mesh" tricks: the mesh-part where i have to enable the top-layers always inserts an artificially inserted closed top/bottom layer at its boundaries -> no help there.....

 

Any help is greatly appreciated!

 

Greetings,

Markus

Stearman solid view.PNG

Stearman With Top Layer.PNG

Stearman inside.PNG

Stearman Without Top Layer.PNG

Edited by Cumulus7
  • Link to post
    Share on other sites

    Posted · Unwanted top layer - or: how to use horizontal layers inside model without a final top layer

    I just tried slicing that using craftware (not that I normally use it for anything other than viewing gcode) and it also filled the part with infill and put a top on it. So maybe the model is just broken in some way?

  • Link to post
    Share on other sites

    Posted · Unwanted top layer - or: how to use horizontal layers inside model without a final top layer

    Yes, that model is definitely weird. S3D also slices it with infill and look at the model before slicing, the rear wall is always missing no matter which way the model is turned.

     

     

    Screenshot_2018-01-27_17-19-17.png

  • Link to post
    Share on other sites

    Posted · Unwanted top layer - or: how to use horizontal layers inside model without a final top layer

    Those walls appear to be infinitely thin.  You need to make them thicker - I recommend 0.5mm minimum  1mm even better.  At 0.5mm walls this thing will be pretty delicate.  At infinitely thin walls, well, there's nothing to print.

  • Link to post
    Share on other sites

    Posted · Unwanted top layer - or: how to use horizontal layers inside model without a final top layer

    None of the walls are manifold. They are all 2D sheets and therefore not able to slice.

    Making the walls 0.8mm with an inside shell (so as not to expand the outer surface) it slices quite well.

    Sliced.thumb.jpg.ed433938310acceafacfe2b32f0a30d6.jpg

     

    Running it through 3DS MA's STL Check I round the errors that confirmed the 2D aspect of the model.

    General number of errors:

    OverallErrors.thumb.jpg.f4986877aa49b15a692620b9c833c482.jpg

     

    When getting into specifics, you can see it is all open edges.

    Specific errors:

    SpecificErrors.thumb.jpg.f40ff473dcab6d101864eadafcbf3024.jpg

     

    Here is the file that I sliced:

    Ste_fuselage_5_08mmWalls.stl

  • Link to post
    Share on other sites

    Posted · Unwanted top layer - or: how to use horizontal layers inside model without a final top layer

    How did you "make them all 0.8mm thick"?  Is there a free program that this guy can use to do that?

  • Link to post
    Share on other sites

    Posted · Unwanted top layer - or: how to use horizontal layers inside model without a final top layer

    I used 3DS MAX. I am not sure what is available for free.

     

    Kinda sucks that these people making these models are not making them correctly for the most part.

     

    The 0.8mm thick was based on your previous suggestions in other threads of making the walls twice the diameter of the nozzle.

  • Link to post
    Share on other sites

    Posted (edited) · Unwanted top layer - or: how to use horizontal layers inside model without a final top layer

    I just found this tutorial on how to do it in Blender.

    Edited by kmanstudios
  • Link to post
    Share on other sites

    Posted (edited) · Unwanted top layer - or: how to use horizontal layers inside model without a final top layer

    THX everybody,

     

    so there is no setting to tell Cura to:

    a) print horizontal geometry

    and

    b) not "invent" or "add" additional geometry?

     

    All the detail is essentially there....

    The shell has no "depth" since it should be printable with a single layer. That seems only possible without a given depth, since no fixed nozzle-size is required.

     

    I might try the blender way though....

     

    For now i help myself with some "cut meshes" that enable the top/bottom layers at some key-points.

    Not perfect, since those cut-meshes generate a top/bottom-layer themselfes, but that layer is not as extensive as a top/bottom layer over the whole wing.

    (other cut-meshes enable a second wall at the start and end of each wing-part)

     

    That kinda works for the wings. I haven't looked at the fuselage yet. 

    (i build the EasyMaxx glider https://3dlabprint.com/shop/easymax-001/)

     

    Greetings,

    Markus

     

    Cut-Meshes.PNG

    Edited by Cumulus7
  • Link to post
    Share on other sites

    Posted · Unwanted top layer - or: how to use horizontal layers inside model without a final top layer
    On 1/27/2018 at 2:18 PM, Cumulus7 said:

    THX everybody,

     

    so there is no setting to tell Cura to:

    a) print horizontal geometry

    and

    b) not "invent" or "add" additional geometry?

     

    All the detail is essentially there....

    The shell has no "depth" since it should be printable with a single layer. That seems only possible without a given depth, since no fixed nozzle-size is required.

    Slicers are designed to slice the models as made, not really compensate for bad modeling. Also, at what point are users asking a slicer to not be a slicer and become a faux modeling program?

     

    The 2D sheet cannot be sliced because it falls below the sampling range of capability. You may see it, but it has no depth and therefore, not 3D. 2D sheets like what you are trying to work with are just flatland......

     

    You may also want to look into the Nyquist Frequency which governs all sampling operations.

  • Link to post
    Share on other sites

    Posted · Unwanted top layer - or: how to use horizontal layers inside model without a final top layer

    is there any way to do what the original post asked for? removing the top/bottom layers but keeping other horizontal faces closed?

    my model is very wide at the bottom, but has overhangs which are left open when i set bottom thickness to 0

  • Link to post
    Share on other sites

    Posted · Unwanted top layer - or: how to use horizontal layers inside model without a final top layer

    The Op's files had to be fixed.

  • Link to post
    Share on other sites

    Posted · Unwanted top layer - or: how to use horizontal layers inside model without a final top layer
    3 hours ago, edwardlego said:

    is there any way to do what the original post asked for? removing the top/bottom layers but keeping other horizontal faces closed?

    my model is very wide at the bottom, but has overhangs which are left open when i set bottom thickness to 0

    A photo would help.  I'm wondering if you are asking for something completely different than kman and I are thinking you are asking about.

     

    Well let me ask you this - when you say "removing top/bottom" do you mean in CAD?  Because if so I think the answer is no.  But if you want to remove them in cura (but they exist in cad) then I think the answer is yes.

     

    If you just put up an infinitely thin wall in cad cura will slice this wall PERFECTLY.  To within a billionth of an inch accuracy.  It will print nothing which is what an infinitely thin wall is: nothing.

  • Link to post
    Share on other sites

    Posted · Unwanted top layer - or: how to use horizontal layers inside model without a final top layer
    4 hours ago, gr5 said:

    A photo would help.  I'm wondering if you are asking for something completely different than kman and I are thinking you are asking about.

     

    Well let me ask you this - when you say "removing top/bottom" do you mean in CAD?  Because if so I think the answer is no.  But if you want to remove them in cura (but they exist in cad) then I think the answer is yes.

     

    If you just put up an infinitely thin wall in cad cura will slice this wall PERFECTLY.  To within a billionth of an inch accuracy.  It will print nothing which is what an infinitely thin wall is: nothing.

    image.thumb.png.c085117d69b79160ef45ac6e06769400.png

    it's about settings in cura. i just want to avoid printing the solid bottom layers, saving hours in some prints, but keep the overhanging bottom layers that aren't touching the buildplate

  • Link to post
    Share on other sites

    Create an account or sign in to comment

    You need to be a member in order to leave a comment

    Create an account

    Sign up for a new account in our community. It's easy!

    Register a new account

    Sign in

    Already have an account? Sign in here.

    Sign In Now
    • Our picks

      • UltiMaker Cura 5.9 stable released!
        Here comes Cura 5.9 and in this stable release we have lots of material and printer profiles for UltiMaker printers, including the newly released Sketch Sprint. Additionally, scarf seams have been introduced alongside even more print settings and improvements.  Check out the rest of this article to find out the details on all of that and more
          • Like
        • 5 replies
      • Introducing the UltiMaker Factor 4
        We are happy to announce the next evolution in the UltiMaker 3D printer lineup: the UltiMaker Factor 4 industrial-grade 3D printer, designed to take manufacturing to new levels of efficiency and reliability. Factor 4 is an end-to-end 3D printing solution for light industrial applications
          • Heart
          • Thanks
          • Like
        • 4 replies
    ×
    ×
    • Create New...