Converting a parabolic curved surface to sheet metal - possible?

[Tulkas33]

Attempting to make flatten-able surfaces with the sheet metal workflow so that I can create flat sewing patterns.

Converting this surface to sheet metal and flattening was no issue when I based the surface's curve on an arc. I now realize the curve needs to be parabolic, but an error says "can't calculate body thickness" when I select the tab.

Am I missing something simple or is it just not possible to convert if it's a parabolic curve rather than an arc?

[Warmingup1953 · Accepted solution]

Sometimes extend using Perpendicular works(better). You need then to add a fillet (small) before thickening away from the fillet. I keep my thickens to paper thin or less when simply making patterns 

[Tulkas33]

Is the fillet a required step? Seems like it would change the dimensions of the flat pattern slightly?

[Tulkas33]

Thank you for your solution. Hoping someone might have an explanation for why this works but the tangent flange does not. A tangent flange would give me a totally accurate pattern if doable. The pattern you showed me is slightly asymmetrical. I'm wondering if the flange is allowing it to distort as it flattens? 

[Warmingup1953]

I didn't dig down into your Timeline, I simply jumped in in "Salvage Mode"! If you were to amend your sketch so as to include a 1mm line tangent to the curve rather than using extension that will probably yield results (Speculation only until I have a look again)