Freestyle > Creating Symmetrical Freestyle Geometry > About Mirroring Mesh Elements
  
About Mirroring Mesh Elements
You can mirror a control mesh by selecting its elements, such as faces or edges, and projecting them onto a mirror plane. Mirroring helps you to create symmetrical Freestyle geometry. The mirror plane can be a datum plane. By default, the mirrored control mesh is not displayed in the graphics window and is dependent on the original mesh. Changes to the original geometry are automatically reflected in the mirrored geometry. You can break and reactivate this dependency by clicking Dependent. When you break the dependency or create independent elements in the dependent mode, the mirrored control mesh is displayed. The portions of the mesh that are still unchanged can be made dependent on the original mesh. Portions of the mesh that have changed since they were made independent cannot be made dependent again. You can create only one mirrored Freestyle feature for a control mesh.
You cannot mirror mesh elements in the following cases:
You select the entire mesh for mirroring.
Selected faces share the edges of an unselected face.
Selected edges share the same unselected face.
Selected edges share the same unselected edge.
A vertex of the selected edges or faces is aligned to another plane.
You can also mirror the mesh that has edges aligned to the external geometry across the reference datum plane. The reference geometry is mirrored in such cases to retain the shape of the aligned edges. The mirrored reference appears as a ghost curve and updates as follows:
If the mirrored geometry is independent, the ghost curve acts as a reference for moving the vertices of the edges along the mirrored side.
If you unlink the aligned edges when the mirrored edge is independent, the ghost curve is removed.
For missing or failed references, the ghost curve is hidden.