Honnestly, I do not remember how I did. May I ask to refresh my mind?
I do not want to have big radius, but some thing to cut my 90° edge.
I wunder, if it would be better to have 45° flat face. What would it better, while I print it why my 3D printer. But I thing that a radius corner is nicer, as shown at the picture.
The top of my top box will be for radius corder, and the bottom of the top of box that I can increase or decrease. But any way, bot part will be the top of the box
What version of SketchUp are you working with? Your profile says Free Web and also 2021. That’s contradictory. Do you mean you are using a cr acked version of SketchUp 2021?
As for radiusing the edges, start with a rectangle with the corners rounded. use that as a path for FollowMe with a profile for the thickness of the box and with the radius corners.