RhinoCommon:从mesh输出obj

https://discourse.mcneel.com/t/get-obj-from-rhinodoc-without-write-in-file/55732/3

  public class TestVictorCommand : Command
  {
    public override string EnglishName = "TestVictor";

    protected override Result RunCommand(RhinoDoc doc, RunMode mode)
    {
      // Select some object
      var go = new GetObject();
      go.SetCommandPrompt("Select object");
      go.SubObjectSelect = false;
      go.Get();
      if (go.CommandResult() != Result.Success)
        return go.CommandResult();

      // Get the selected RhinoObject
      var rh_obj = go.Object(0).Object();
      if (null == rh_obj)
        return Result.Failure;

      // You cannot serialize a RhinoObject. But you can serialize
      // its properties.

      // Convert Geometry and Attributes to bytes
      var geometry_bytes = ConvertCommonObjectToBytes(rh_obj.Geometry);
      var attributes_bytes = ConvertCommonObjectToBytes(rh_obj.Attributes);
      if (null == geometry_bytes || null == attributes_bytes)
        return Result.Failure;

      // TODO...

      // Create Geometry from bytes
      var common_object = CreateCommonObjectFromBytes(geometry_bytes);
      var new_geometry = common_object as GeometryBase;

      // Create Attributes from bytes
      common_object = CreateCommonObjectFromBytes(attributes_bytes);
      var new_attribues = common_object as ObjectAttributes;

      // Validate
      if (null == new_geometry || !new_geometry.IsValid || null == new_attribues || !new_attribues.IsValid)
        return Result.Failure;

      new_attribues.ObjectId = Guid.Empty;
      doc.Objects.Add(new_geometry, new_attribues);
      doc.Views.Redraw();

      return Result.Success;
    }

    public static byte[] ConvertCommonObjectToBytes(CommonObject src)
    {
      if (null == src)
        return null;

      byte[] rc = null;
      try
      {
        var formatter = new BinaryFormatter();
        using (var stream = new MemoryStream())
        {
          formatter.Serialize(stream, src);
          rc = stream.ToArray();
        }
      }
      catch (Exception e)
      {
        Debug.WriteLine(e.Message);
      }

      return rc;
    }

    public static CommonObject CreateCommonObjectFromBytes(byte[] bytes)
    {
      if (null == bytes || 0 == bytes.Length)
        return null;

      CommonObject rc = null;
      try
      {
        using (var stream = new MemoryStream())
        {
          var formatter = new BinaryFormatter();
          stream.Write(bytes, 0, bytes.Length);
          stream.Seek(0, SeekOrigin.Begin);
          var obj = formatter.Deserialize(stream) as CommonObject;
          if (null != obj)
            rc = obj;
        }
      }
      catch (Exception e)
      {
        Debug.WriteLine(e.Message);
      }

      return rc;
    }
  }

 meshObjRefs = Rhino.DocObjects.RhinoObject.GetRenderMeshes(doc.Objects.GetObjectList(object_enumerator_settings), true, false);
             if (null != meshObjRefs)
             {
                 for (int i = 0; i < meshObjRefs.Length; i++)
                 {
                     Mesh mesh = meshObjRefs[i].Mesh();
                     foreach (Rhino.Geometry.Point3f point in mesh.Vertices)
                     {
                         s.Append("v ");
                         s.Append(point.X.ToString(_allFloatDigits));
                         s.Append(" ");
                         s.Append(point.Y.ToString(_allFloatDigits));
                         s.Append(" ");
                         s.Append(point.Z.ToString(_allFloatDigits));
                         s.Append(System.Environment.NewLine);
                     }
                     vertex = mesh.Vertices.Count;
                     foreach (Rhino.Geometry.Point2f point in mesh.TextureCoordinates)
                     {
                         s.Append("vt ");
                         s.Append(point.X.ToString(_allFloatDigits));
                         s.Append(" ");
                         s.Append(point.Y.ToString(_allFloatDigits));
                         s.Append(System.Environment.NewLine);
                     }
                     foreach (Rhino.Geometry.Vector3f point in mesh.Normals)
                     {
                         s.Append("vn ");
                         s.Append(point.X.ToString(_allFloatDigits));
                         s.Append(" ");
                         s.Append(point.Y.ToString(_allFloatDigits));
                         s.Append(" ");
                         s.Append(point.Z.ToString(_allFloatDigits));
                         s.Append(System.Environment.NewLine);
                     }
                     foreach (Rhino.Geometry.MeshFace face in mesh.Faces)
                     {
                         A = face.A + shift;
                         B = face.B + shift;
                         C = face.C + shift;
                         s.Append("f ");
                         s.Append(A);
                         s.Append("/");
                         s.Append(A);
                         s.Append("/");
                         s.Append(A);
                         s.Append(" ");
                         s.Append(B);
                         s.Append("/");
                         s.Append(B);
                         s.Append("/");
                         s.Append(B);
                         s.Append(" ");
                         s.Append(C);
                         s.Append("/");
                         s.Append(C);
                         s.Append("/");
                         s.Append(C);
                         if (face.IsQuad)
                         {
                             D = face.D + shift;
                             s.Append(" ");
                             s.Append(D);
                             s.Append("/");
                             s.Append(D);
                             s.Append("/");
                             s.Append(D);
                         }
                         s.Append(System.Environment.NewLine);
                     }
                     foreach (Rhino.Geometry.Vector3f point in mesh.FaceNormals)
                     {
                         s.Append("#fn ");
                         s.Append(point.X.ToString(_allFloatDigits));
                         s.Append(" ");
                         s.Append(point.Y.ToString(_allFloatDigits));
                         s.Append(" ");
                         s.Append(point.Z.ToString(_allFloatDigits));
                         s.Append(System.Environment.NewLine);
                     }
                     foreach (Rhino.Geometry.Point3d point in mesh.TopologyVertices)
                     {
                         s.Append("#tv ");
                         s.Append(point.X.ToString(_allFloatDigits));
                         s.Append(" ");
                         s.Append(point.Y.ToString(_allFloatDigits));
                         s.Append(" ");
                         s.Append(point.Z.ToString(_allFloatDigits));
                         s.Append(System.Environment.NewLine);
                     }
                     shift += vertex;
                 }
             }