Spline Mirror Modifier

Similar to the Symmetry modifier, the Spline Mirror modifier duplicates a spline along a specified axis. Any present normals are also duplicated.

Select a spline. > Modify panel > Modifier List > Object Space Modifiers > Spline Mirror

Procedures

To use the Spline Mirror modifier:

Select a spline.
On the Modify panel > Modifier List, select Object-Space Modifiers > Spline Mirror.

The spline is automatically duplicated along the specified axis.

A Rubin vase created by applying a Spline Mirror modifier onto an editable spline.

Represents the axis of the mirror effect. You can move, rotate or scale the gizmo to affect the mirroring as well as animate the transforms.

Displays knots on the spline.

Sets the axis along which to mirror the spline: either X, Y, or Z.

Sets the size of the mirror gizmo in the viewport.

When enabled, slices the portion of the spline that falls on the opposite side of the mirror so it is not reflected.

When the gizmo is outside the boundaries of a spline, the symmetrical reflection is still treated as part of the original shape.

Inverts the direction of symmetry.

When enabled, welds the start and end knots from the original and reflected splines when they fall within the specified threshold.

Sets the proximity threshold for welding knots.

Keeps the tangents for retained knots.