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Increase resolution of exported STL

I am exporting a part studio as an STL with a resolution of "fine". What are the highest quality custom settings that I can use? The design have a very subtle and large radius curve that is more flat than round in the final part when I load the STL into my slicing software. I am 3D printing this and I need a nice gentle sweeping curve, not the small bump where the vertices of the two flat planes making the curve intersect.


  • billy2billy2 Member, OS Professional, Mentor, Developers, User Group Leader Posts: 1,945 PRO
    edited December 2018
    Re-import the stl into OS and look at it.

    You can even put both into an assembly and compare.

    I'm using fine and have no issues, but only you can decide.

    There's no limit except the size of the file that's generated.

  • jacob_birkettjacob_birkett Member Posts: 2
    But I need to know how to tweak the numbers. For example, what is 2x whatever "Fine" is?
  • lemon1324lemon1324 Member, Developers Posts: 217 EDU
    I'm pretty sure you can set everything as fine as you want using custom settings - once you're in custom settings though, it's probably better to define what acceptable tolerances are and set the parameters to meet those instead of trying to figure out what "2x fine" would be.
    Parameters function as follows:
    • Angular deviation: the maximum angle allowed between two adjacent faces of the STL.
    • Chordal tolerance: the maximum normal distance from an STL facet to the "true" model.
    • Minimum size: this is mostly to reduce extremely small facets from odd interactions of the above two and your model geometry.
    In your case, probably reducing the chordal tolerance will help smooth things.  That being said, if you're 3D printing this, think about what your tolerances are - my lab prints stuff on very good printers and we still don't need to go beyond "fine."  Often faceting on STLs is visually apparent, but adds less stackup than printing tolerances.
    Arul Suresh
    PhD, Mechanical Engineering, Stanford University
  • jon_sorrellsjon_sorrells Onshape Employees Posts: 51
    But I need to know how to tweak the numbers. For example, what is 2x whatever "Fine" is?
    The "Fine" setting uses a chordal tolerance of 0.06 mm.  This is probably the one you want to change.
  • David_BoneDavid_Bone Member Posts: 47 PRO
    Just set to the resolution you want to check (Coarse, Medium, or Fine) then switch back to Custom and you can see the settings.

    For me it's...
        Angular deviation (deg): 12.5
        Chordal tolerance (mm): 0.24
        Minimum facet width (mm): 0.635
        Angular deviation (deg): 6.25
        Chordal tolerance (mm): 0.12
        Minimum facet width (mm): 0.254
        Angular deviation (deg): 2.5
        Chordal tolerance (mm): 0.06
        Minimum facet width (mm): 0.0254

    Hope this helps!
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