llnl / llnl/conduit

Documentation -- Example Triangle mesh has bad connectivity

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Description

On the https://llnl-conduit.readthedocs.io/en/latest/blueprint_mesh.html#tris example, I think that the connectivity for the "odd" numbered triangles is incorrect. For all of the "even" triangles, the connectivity progresses clockwise around the element; for the "odd-numbered" triangles, the connectivity progresses counter-clockwise around the element. I think that they should be consistent -- either all CW or all CCW.

topologies: 
  mesh: 
    type: "unstructured"
    coordset: "coords"
    elements: 
      shape: "tri"
      connectivity: [0, 3, 4, 0, 1, 4, 1, 4, 5, 1, 2, 5, 3, 6, 7, 3, 4, 7, 4, 7, 8, 4, 5, 8]

image

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Open the linked blueprint_mesh.html#tris documentation and inspect the "tris" example's connectivity list alongside the shown mesh image. Determine the intended winding convention, then update the example so the even and odd triangles use the same orientation; the example should be internally consistent when reviewed against the image.

Written by the indexing model from the issue text.

Assessment

Domain
documentation
Issue type
Documentation
Difficulty
2/5
Estimated time
1-3 hours
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
38/100

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