About Using Relief
Use relief to help control the board material and to prevent unwanted deformation when performing unbend operations. Relief allows you to better represent an accurate, real life model that reflects material stretching.
You can add relief while creating a flat segment, or when adding a bend feature. You can set the relief type for each bend end individually or create sets of relief. To maintain consistency and save time, set default bend relief properties using the Relief area of the Preferences dialog box. Default relief settings are displayed in the Relief line of the Model Properties dialog box.