To create this piece:
Go to the 2D window.
On the back right piece (numbered 1), select the left edge of the piece. When selected, the edge is highlighted.
Go to the Context view.
In the Actions section, at Edge Symmetry, click Create.
VStitcher creates a symmetrical copy of the back right piece and combines it with the original piece. The back right piece and back left piece are one piece. The piece looks like this:
Save the file: on the Main toolbar, click .
Once you have created the front left piece, continue with Creating the Other Sleeve.