Help with a blend

[TS3g]

I'm trying to help fix some rectangular tube models that have copes on the ends that will be cut on a tubing plasma cutter. We have been just using an extrude with a specific profile for the cope and it has worked fine on square cuts. However, when the cut is at an angle, the plasma cutter can't follow the profile and refuses to cut it. The company that made the plasma cutter came up with a fix on the angled copes, which basically creates a blended edge at the corner instead of a hard edge. However, I can't figure out for the life of me how to make the blend like they did. Can anyone point me in the direction of what tools to use or how to accomplish this?

Here's what I have:
View attachment 5162

And here is what I want:
View attachment 5163

Thanks,
Tyler

 

[kenppy]

Make a blended surface using these four edges [the two shown and the joining ones] and solidify.
View attachment 5164

 

[TS3g]

Thanks, that was what i was trying to do, but couldn't make it work. Turns out the inside curve was split into two, so I wasn't selecting the right cross curve to make the blend. Got it figured out now and it works. Thanks though.

View attachment 5165

 

[design-engine]

don't use thicken