Sometimes it is better to have a sheet with continuous outer contour than a sheet with processing such as cuts & polycuts. For example, stretching is often easier if you can stretch the contour directly. So, this Wiki will help you with converting a metal sheet to match its continuous outer contour.
Click on Steel > Home > Edit Steel Elements > Modify. In the Modify dialog box, there is a function for this i.e. the Match Edges in the Edges section of the Plates tab. This button deletes all machining and adjusts the outer contour accordingly. However, the processing must have been created perpendicular to the top view, i.e. all plate edges have an angle of 90 degrees.
Now the plate has only the outer contour and can be stretched more easily.