I want to make a section view of a solid (or sometimes the assembly) which is an arc shape. I am interested in "theoretical" flattened view - linear lengths etc. I am trying to section with an arc, but receive an error:

The sectioning sketch is an arc with two lines at ends. This is a simple extrude (it is for this example, but in reality I have assemblies - so I can not use sheet metal flat pattern as a workaround)

On the other hand, it seems that an arc is allowed to section the view. This is another example:

This is also a sectioning with arc+2lines, and seems to be working fine

I have tried to section with arc in some different situations during time with different SW versions, and never understood what was the limitation that was giving error like in the first picture, or any other misbehavior that I can not remember now

So, it is possible to section an "arc-shaped-model" with the arc? If so, then how?

Thank you for your help