Move or copy nodes symmetrically with respect to a particular Mirroring
Plane.
From the Main
Menu select Model > Nodes > Mirror.
Select Geometry
> Nodes > Mirror in the Menu tab of the Tree Menu.
Click Mirror Nodes in the Icon Menu.
Shortcut key:
[Ctrl]+[Alt]+6
Click to the right of Mirror Nodes: Display the Node Table
Start Node Number
Enter a starting node number for the newly
created nodes. This number is auto-set to the largest node number in use
+1. To modify this item, click and select on option to specify
a desired number.
Mode
Copy:
To copy nodes
Move:
To move nodes
Reflection
Assign the mirroring plane
y-z plane: Mirroring plane is parallel to the y-z
plane
x:
x coordinate of the mirroring plane
x-y plane: Mirroring plane is parallel to the x-y
plane
z:
z coordinate of the mirroring plane
z-x plane: Mirroring plane is parallel to the z-x
plane
y:
y coordinate of the mirroring plane
Plane defined
by 3 pts.: Mirroring plane is an arbitrary plane
x1, y1, z1: x, y, z coordinates of the 1st point defining
the mirroring plane
x2, y2, z2: x, y, z coordinates of the 2nd point defining
the mirroring plane
x3, y3, z3: x, y, z coordinates of the last point
defining the mirroring plane
The coordinates of the three points may be
directly typed in on the keyboard. Alternatively, click the relevant entry
field and the desired point in the working window to enter the x, y, z
coordinates.
Merge Duplicate
Nodes
Merge overlapping nodes to single nodes if new nodes coincide with existing
nodes. Click to modify the Merging Tolerance.
Copy Node
Attributes
Select the option whether to copy the attributes (nodal boundary conditions,
nodal concentrated loads, etc.) to the nodes being copied. Click to assign desired attributes selectively.
Intersect
Frame Elements
Select the option whether to divide the existing line (beam & truss)
elements at the newly created nodes that intersect the elements. Click
to modify Intersecting Tolerance.
to the right of 
Start Node Number
y-z plane