Vex Fusion 360


I am a beginner to Fusion 360, and Vex fusion 360. I imported the library, anyway show a cut aluminion. For example, I imported 35 holes aluminium 2x c channel but I want a cutted 30 holes aluminion, how do i do that?

You can create a rectangular sketch above the part and extrude it through the channel as a cut. I, however, reccomend this library and add in for fusion 360