Creates a mirrored copy of an element about a given plane. 
   Namespace:   Autodesk.Revit.DB  
  Assembly:   RevitAPI  (in RevitAPI.dll) Version: 22.0.0.0 (22.1.0.0) 
  Since:  2012 
Syntax
| C# | 
|---|
   |  
| Visual Basic | 
|---|
   |  
| Visual C++ | 
|---|
   |  
Parameters
- document
 -  Type:  Autodesk.Revit.DB Document  
The document that owns the element. 
- elementToMirror
 -  Type:  Autodesk.Revit.DB ElementId  
The element to mirror. 
- plane
 -  Type:  Autodesk.Revit.DB Plane  
The mirror plane. 
Examples
public void MirrorWall(Autodesk.Revit.DB.Document document, Wall wall)
{
    Reference reference = HostObjectUtils.GetSideFaces(wall, ShellLayerType.Exterior).First();
    Face face = wall.GetGeometryObjectFromReference(reference) as Face; // get one of the wall's major side faces
    UV bboxMin = face.GetBoundingBox().Min;
    Plane plane = Plane.CreateByNormalAndOrigin(face.ComputeNormal(bboxMin), face.Evaluate(bboxMin).Add(new XYZ(10, 10, 0)));
    // create a plane based on this side face with an offset of 10 in the X & Y directions
    ElementTransformUtils.MirrorElement(document, wall.Id, plane);
} Public Sub MirrorWall(document As Autodesk.Revit.DB.Document, wall As Wall)
    Dim reference As Reference = HostObjectUtils.GetSideFaces(wall, ShellLayerType.Exterior).First()
    Dim face As Face = TryCast(wall.GetGeometryObjectFromReference(reference), Face)
    ' get one of the wall's major side faces
    Dim bboxMin As UV = face.GetBoundingBox().Min
 Dim plane As Plane = Autodesk.Revit.DB.Plane.CreateByNormalAndOrigin(face.ComputeNormal(bboxMin), face.Evaluate(bboxMin).Add(New XYZ(10, 10, 0)))
    ' create a plane based on this side face with an offset of 10 in the X & Y directions
    ElementTransformUtils.MirrorElement(document, wall.Id, plane)
End Sub Exceptions
| Exception | Condition | 
|---|---|
| Autodesk.Revit.Exceptions ArgumentException | elementToMirror cannot be mirrored. -or- The element elementToMirror does not exist in the document | 
| Autodesk.Revit.Exceptions ArgumentNullException | A non-optional argument was null |