Create and modify 3D models > Create 2D geometry > Change 2D geometry > Mirror 2D geometry
  
Mirror 2D geometry
To save time when creating symmetrical profiles you can mirror them about a line or point of symmetry.
To mirror 2D geometry,
1. Click Modeling and then, in the Modify 2D group, click More.
2. Click Mirror under Transform. The Mirror dialog box opens.
3. Select the geometry to be mirrored.
4. If you do not want to keep the original geometry, clear Keep Elem.
5. Now you can choose the type of mirror you want. Click one of the following buttons in the Mirror dialog:
Two Points: Click two points in the workplane.
Edge: Click a straight edge in the geometry.
Horizontal: move the mouse across the workplane to preview the mirror; click to position in the desired location.
Vertical: same as Horizontal.
Center: same as Horizontal.
6. Click Apply if you have deselected Keep Elem.
7. Click to complete the operation.