Working with Sheet Metal Parts - Inventor 2013 and Inventor LT 2013 Essentials - page 231

7. Switch to the Size tab of the PunchTool dialog box, and set the Length
value to 60 mm and the Height value to 4 mm, as shown in Figure 10.14.
(The preview will not update.)
FIGURE 10.14 Placing the punch tools on the part
8. Click Finish to build the features.
Now, you need to restore the part to its original shape. This requires
the punch tools to be bent with the other geometry.
9. Click the Refold tool in the Modify panel.
10. Once again, use the top face as the stationary reference, and click the
only unfold feature that highlights.
11. Click OK to restore the shape of the part, as shown in Figure 10.15.
12. Move your end-of-folded marker to the bottom of the list to expose
the cut sketch.
13. Edit the cut sketch by double-clicking it in the Browser.
FIGURE 10.15 The part's bend restored