How to get selected mesh edge in RhinoCommon

Rhino Developer
1

To get selected mesh edge, seems there is a function named MeshComponentRef in c++, but not in RhinoCommon, is there any method to get selected edge in RhinoCommon?

gf.Object(0).MeshComponentRef()

2

We just published a new extensive guide on rhinocommon in grasshopper. This is the section on meshes, does it help? Rhino - Chapter 3: RhinoCommon Geometry

3

Hi Scott,
I would like to get picked edge of mesh, just as the code below, but not cpp

 CRhinoGetObject go;
  go.SetCommandPrompt(L"Select mesh");
  go.SetGeometryFilter(CRhinoGetObject::mesh_object);
  go.GetObjects(1, 1);
  if (go.CommandResult() != CRhinoCommand::success)
    return go.CommandResult();

  const CRhinoMeshObject* mesh_object = CRhinoMeshObject::Cast(go.Object(0).Object());
  if (0 == mesh_object)
    return CRhinoCommand::failure;

  CRhGetMeshFaceRef gf(mesh_object->RuntimeSerialNumber());
  gf.SetCommandPrompt(L"Select mesh edge");
  gf.SetGeometryFilter(CRhinoGetObject::meshedge_filter);
  gf.GetObjects(1, 1);
  if (gf.CommandResult() != CRhinoCommand::success)
    return gf.CommandResult();

  const ON_MeshComponentRef* mesh_edge_ref = gf.Object(0).MeshComponentRef();
  if (nullptr == mesh_edge_ref)
    return CRhinoCommand::failure;

  RhinoApp().Print(L"Selected mesh edge index = %d\n", mesh_edge_ref->MeshTopologyEdgeIndex());
4

The thread here:

is about faces but does it help?

5

I think this might be what you were trying to do:

    protected override Result RunCommand(RhinoDoc doc, RunMode mode)
    {
      GetObject go = new GetObject();
      go.GeometryFilter = ObjectType.MeshEdge;
      
      while (true)
      {
        GetResult gr = go.Get();
        if (gr == GetResult.Cancel)
          return Result.Cancel;
        if (gr == GetResult.Object)
        {
          ObjRef obj = go.Object(0);
          if (obj.GeometryComponentIndex != null)
          {
            if (obj.GeometryComponentIndex.ComponentIndexType == ComponentIndexType.MeshTopologyEdge)
            {
              RhinoApp.WriteLine($"Selected topology edge {obj.GeometryComponentIndex.Index}");
            }
          }
          break;
        }
      }
      return Result.Success;
    }
7

I think “GeometryComponentIndex.Index” is what I want, thanks.

8

great! it works well, thanks for your help

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