Convert a line or curve to a parallel line with closed ends for hatch?

Hi,
V5
I have used Rhino to create a line art of an aircraft for a T shirt embroidery.

I need to convert all the lines into parallel lines with closed ends to give hatch to.
So we can see what a 0.5mm thread or in this case a 0.2mm thread would look like.

As we all know the more you zoom out the thicker relatively the lines look in print preview,

so what looks ‘do-able’ as thread thickness goes thin and beyond thread choices zoomed in.

what command converts a line or curve into parallel of same with closed ends ?

sort of offset both sides by 0.1mm deleting original centre line (or keeping that on the original layer and placing result on new layer, and close both ends.

Cheers

Steve

Try Offset, Cap=your choice