The Unfold and Fold features can be very useful when making cuts across bends that could not be made in the folded state. Here's an example of how this can be done:

1. Continuing on from the previous model, delete the Fold feature, but leave the earlier Unfold feature. This should leave an unfolded model with a rough cross shape.
2. Start a sketch on the top face of the part and use the Circle tool to draw a 50mm-diameter circle that straddles one of the bend areas, as illustrated in Figure 5.6. Note: you can use the Midpoint Relation along the bent edge to anchor the circle in place:

Figure 5.6: Creating a circle sketch on the top face of the unfolded part

3. Use the circle sketch with an Extruded Cut to create a circular cut all the way through the sheet.
4. Now, re-fold the part by selecting the Fold tool, choosing the Fixed Face, pressing Collect All Bends, and then pressing OK.

This should create a folded...