A contour flange along the 3 edges would automatically miter those corners.
Edit: Uh, maybe not
Hi there @lifofadrafter,
Normally I would just use a contour flange to get those corners mitered automatically.....but in this case, you could just modify the side angle of the flanges, retrospectively.
Design Manager Streetscape Ltd
Solid Edge 2019 [MP2] Classic [x3 Seats - Cloud Enabled]
Windows 10 - Quadro P2000