You can create symmetry curves in the NX sketching by using the “Mirror” command located in the “Home Ribbon Bar” as shown in the figure.

To create symmetry curves:
- Start the “Mirror” command.
- The “Mirror” command dialog box will open.
- If you want to create a symmetry constraint relation between the selected object and the created symmetry object turn on the box near the “Create Persistent Relation” text.
- The selected centerline will be the referance curve after the “Mirror” command. If you do not want the centerline to be the reference object, turn off the checkbox near the “Convert Centerline to Reference” text.
- Select curves to mirror (the “Select Curve” bar is highlighted.)
- Click the middle mouse button once to activate the “Select Centerline” bar.
- Select Centerline.
- The mirrored object preview will appear on the graphics screen.
- Click the “Ok” button in the command dialog box to create the symmetric curves.
Note: You can select the model objects (3d model edges) out of the sketch to create mirrored curves in the sketch.
To select out of sketch objects to mirror.
- Start the “Mirror” command.
- Set the selection scope to “Within Work Part Only” as shown in the figure.
- Select the model edges to mirror.