First draw a test copper skin
Then click on the copper skin editing mode. This is the button I released on the toolbar. If it is not released, you can click the Setupmenu, and then click to Application Modeswitch to ShapeEditthe mode. I circled it with a graffiti pen in the lower right corner, and the program mode is marked here. There are two points in learning allegro that are always accompanied by the operation. One is the operation mode, which is the words next to the green box in the lower left corner of the status bar, and the other is the program mode. 
After entering the copper skin editing mode, you can modify the parameters, as shown in the figure below
Then move the mouse close to the corner of the copper skin, the mouse will become a big cross, click to chamfer.
Of course, there are also situations where chamfering fails. The first find panel must be all on, and the angle of the second chamfering cannot be greater than the height of the copper skin, that is, it cannot be bald directly, just like peeling off a piece. The latter error is Will give a prompt:Trim value is greater than length of short corner side.
Paste the rectangle after the chamfering is completed below. You can see that only two corners were successfully inverted, and the second error was reported when the remaining two corners were operated again.
