Choose Home tab→Sheet Metal group→Corners list→Break Corner 
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Select the edge or edges you want to break.
Use the command bar boxes to define break characteristics.
Finish the feature.
Choose Home tab→Sheet Metal group→Break Corner .
Use the QuickBar options to specify either a radius corner or chamfer corner.
Select the edge or edges you want to break.
Type a value for the radius or chamfer.
Click to finish the feature.
Tip:
You can select the break option before or after selecting the edges you want to break.
You can set the selection type to Face to apply the break to all thickness edges of the selected face, including all interior and exterior thickness edges.
