Find and check plane from curve or surface

Hello all :slight_smile:
i try to nesting section of my surface.

but i stuck in find a plane form section curve.

I cannot understand list number 0~1,9~12 is not a xy plane(i think that list make error in nesting componet)

can i know why i fail make a plane from curve and how to check next time?

now i make a section cureve spread to another plan for a fabrication.

test1.3dm (155.1 KB) (16.7 KB)