public esriGeometryType ShapeType {get;}

{
  //must support editing!
  if (!featSceneLayer.HasAssociatedFeatureService ||
      !featSceneLayer.IsEditable)
  {
    //not supported - exit the function
  }

  //Check geometry type...must be point in this example
  var editOp = new EditOperation()
  {
    Name = "Create new 3d point feature",
    SelectNewFeatures = true
  };

  var attributes = new Dictionary<string, object>();
  //mapPoint contains the new 3d point location
  attributes.Add("SHAPE", mapPoint);
  attributes.Add("TreeID", "1");
  editOp.Create(featSceneLayer, attributes);
  editOp.ExecuteAsync();
}