ArcGIS Pro 3.4 API Reference Guide
ArcGIS.Core.CIM Namespace / CIMBasicFeatureLayer Class / IsFlattened Property
Example Version

IsFlattened Property (CIMBasicFeatureLayer)
Gets or sets a value indicating whether the layer is flattened.
Syntax
public bool IsFlattened {get; set;}
Example
Move a layer in the 2D group to the 3D Group in a Local Scene
//The layer in the 2D group to move to the 3D Group in a Local Scene
var layer = MapView.Active.Map.GetLayersAsFlattenedList().OfType<FeatureLayer>().FirstOrDefault();
QueuedTask.Run(() =>
{
  //Get the layer's definition
  var lyrDefn = layer.GetDefinition() as CIMBasicFeatureLayer;
  //setting this property moves the layer to 3D group in a scene
  lyrDefn.IsFlattened = false;
  //Set the definition back to the layer
  layer.SetDefinition(lyrDefn);
});
Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3 or higher.
See Also