When dealing with the water jet, when inputting the BO shortcut key alone to close the polyline area, it reminds that the closed boundary cannot be determined, and the processing method for the appearance of small circles is as follows:

1. Select the processed lines of the graphic with a box, input the CO shortcut key to copy and move it to the right

2. Delete the processed line segments on the left pattern and keep the unclosed line segments on the left.

3. Copy and move out the multiple line areas that cannot be closed separately, and then separate them into individual areas. Input the BO shortcut key to close the polyline of each individual area.

4. After all the unclosed areas are moved out and closed separately, you can move the patterns that have been processed with BO alone back to the graphic area processed in the first step, and then input MY to generate the face domain.