Failed to extrude sections, check input.

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  john_mcclary Member, Developers Posts: 3,909 PRO

  February 2022

  hard to tell from a screen shot, for better help it is always best to link your document.
  
  But I would assume the two stars on the top of the C's curve are exactly touching the edge of the curve. This may be creating a zero-thickness edge.
  Try sliding the stars down slightly using transform and see if that works.
  (or make those two stars construction lines so they are ignored for now)

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  NeilCooke Moderator, Onshape Employees Posts: 5,439

  February 2022

  It will be the stars at the top that touch the edge of the logo - they are creating non-manifold edges (you don't want to know, other than this condition is not allowed). Move them slightly in the sketch so that they either keep or remove a small amount of geometry and it should be OK.

  Senior Director, Technical Services, EMEAI

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  andrew_kleinert Member Posts: 47 PRO

  February 2022

  I came across a similar problem. 
  
  It was complex geometry that was triggered by a variable change.  Suddenly my parts became a sea of red "Boolean Operation failed to return a valid part" for no obvious reason.  A bunch of time was spent pulling the design apart to deconstruct what was going on, googling lots, a bit of learning about what "non-manifold edges" are before I figured it out. 
  
  I have reconstructed a very simple instance of the problem below ...
  
  
  
  Link to doc: https://cad.onshape.com/documents/1e38feb1afe46c1dc690dff0/w/029a649ba1e9e14491d9f344/e/0d748252251589fca813f209?renderMode=0&uiState=620af2609861fd1f00fd2869
  
  
  @NeilCooke , a few questions about this ... 
  
  The system doesn't seem to be very helpful:  "<Tree item> did not regenerate properly:  Boolean operation failed to return a valid part" isn't a helpful error message for something that is physically realisable (within tolerance).  Plus there appears to be a lot more coloured red than needs to be (should it only be the singular non-manifest edge that is indicated red?) - and this gets a lot worse very quickly for more complex shapes. 
  
  ... Should I raise an improvement request?  If so, should it be "Fix non-manifold edge / point handling in renderer"? or "Improve UX around non-manifold edges / point errors"? or something else?
  

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  S1mon Member Posts: 2,419 PRO

  February 2022

  This is a fundamental issue with the Parasolid Kernel that Onshape, Solidworks, NX, and countless other systems use. You basically can't have two bodies join at a line. There needs to be some small amount of overlap.

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  Nic_J Member Posts: 14 EDU

  February 2022

  I believe you must move the starts connecting with the highlighted piece. They're what stop the extrude from happening.

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  andrew_kleinert Member Posts: 47 PRO

  February 2022

  S1mon said:

  This is a fundamental issue with the Parasolid Kernel that Onshape, Solidworks, NX, and countless other systems use. You basically can't have two bodies join at a line. There needs to be some small amount of overlap.

  Thanks for this 👍
  
  I do wonder if the CAD system is able to be more helpful though?  Does the parasolid kernel return error details that can be of more help to the user?
  
  The example I posted above is a fairly simple and a more obvious one.  But when the design is more complex, and the issue arises from a variable change, it can be frustratingly difficult to figure out what is going on (well, it is for me anyway 😀)
  
  Anyway, this is all in the spirit of continual improvement - I’m not complaining.

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