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[CAD formats] Degenerate triangles in STL for use in sHM

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Old   September 20, 2017, 06:22
Question Degenerate triangles in STL for use in sHM
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I've been working on an STL file (shown in this image):

My aim is to use this STL in snappyHeyMesh, however when running the surfaceCheck utility illegalFaces as well as problemFaces appear. In this image the bad triangles can be seen easily:

Therefore, I am worried that the final mesh will turn out badly, or not turn out at all!

I have previously used a no-thickness version of this STL and although problemFaces appeared the mesh turned out ok.

To clarify, I did not make this STL in a CAD software, instead I exported it from a mathematical modelling software called MathMod.

So my question is: can this be an issue? If so, what could I do to improve triangle quality while retaining the same shape?

Thank you
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Old   September 27, 2017, 11:17
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I don't want to be one of those guys who solves his problem and does not give any advice for people with the same issue, so here we go:

I found two main options to improve STL quality though third party software:

  1. Blender

    I liked cellBlender in particular, which is a version of Blender with extra features directed towards chemistry/biology cell and molecule research. However, its Mesh Analyzer and tutorials about how to repair and remesh were fantastic. For the degenerate triangles in STLs try decimating your geometry.
  2. Meshlab

    Many mesh operations (filters as they call them) are based on research papers which is great if you need to give proof of what you do to your geometry. The best option in this software for cleaning (or downsizing) your STL or OBJ files is the Quadratic Edge Collapse option, a good guide can be found here.
I hope this informations helps someone someday.
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illegal face, snappyhexmesh, stl file

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