Carving on sheet-metal body surface!

Hi all,

I have a question and I hope you guys can help me.
I would like to see on one of the faces of a sheet-metal model a carfed
single-line contour and that this is also visible in a step or iges exported when.

Where I am looking for is similar as feature "split line".
You split one side of the face and let the other side unharmed.

I would like to place a sketch on one of the faces with external references if there are any.
And these lines in this sketch do not hit the outer contour or this contours are not closed just a single line.

Ik hope you can help me.!

Robin.

SolidworksParts And Features