Cannot create flat profile or sheet metal or select stationary surface

[kevanromero]

Hello,

I'm trying to flatten this "taco" design. I want to use the outer surface to create a profile so I can cut out the shape. This has worked for me on a similar design, so I know I'm at least going down the right direction, but I don't know where I'm going wrong here.

This design is a shape I have cut/split between two intersecting tubes, to produce this taco-shape, which I then shelled to my desired sheet metal thickness. Weirdly, I could not shell it outwards, I could only create a shell inwards. I think that is also a problem.

I've looked up various ways to select the edge/perimeter. I can select the flat faces and copy/paste them into a new sketch, but I cannot select the curved edges. This probably isn't the right way to do it though. I don't know what else to try.

Thanks!

[davebYYPCU]

Because you only need the outside faces for the Flat Pattern, 

Surface > Create Offset At zero.  Thicken it.

Convert to Sheet Metal, and it will Flat Pattern.

Not able to check the file at the moment, can see it, so don’t know what’s in it.  Those trimmed scalloped edges don’t work in Sheet Metal.

Might help 

[kevanromero]

I did as you said, I made a surface with a zero offset, and I thickened it to what I need. However, I still cannot create a flat pattern because I cannot select a stationary surface.

Thank you for the help. I imagine the problem exists upstream.

[davebYYPCU · Accepted solution]

Worked for me, top flat face,

Might help

[kevanromero]

I know what I did wrong:
I forgot the step of "Convert to Sheet Metal". I find it dumb that there's a button to create a flat pattern, but I have to open the drop-down menu to create the sheet metal part first. Wow, okay, but yes now it works. I swear I've done this before, I just forgot that one step!

And thanks to you, I now know a new step--I've never tried creating a surface before, and then thicken, that was cool.

Thank you!