Working with Sheet Metal Parts - Inventor 2013 and Inventor LT 2013 Essentials - page 226

8. Select the Corner Edit tool at the top-left corner of the part.
9. When the Corner Edit dialog box opens, click the Corner Override
check box, and select Reverse Overlap from the drop-down. See
Figure 10.8.
FIGURE 10.7 Corners that would otherwise overlap are automatically
mitered.
FIGURE 10.8 The automatic corner
treatments can be overridden.
10. Click OK to accept the corner edit and then OK to place the flanges.
11. Start the Flange tool again, and click the front edge of the new flange
on the angled face. (See Figure 10.9.)
12. Expand the dialog box to see additional options, set Width Extents
Type to Offset, and change the offset values to 10 mm.
13. Change Flange Height to 15 mm, as shown in Figure 10.9, and click
OK to place the feature.