Help converting lines/edges to double lines: Trying to draw stained glass windows

I have sketched an elevation of my stained glass windows using single line edges to represent the 8mm lead work. I now want to convert the edges that represent the lead into 8mm double lines. There is an extension called “double line” which I though was going to work perfectly but alas it only seems to operate on very simple shapes. Does anyone have any ideas / extensions that will quickly convert this?

leadwork2.skp (120.2 KB)

You can use the native Offset tool to offset each face 4mm into each pane, then afterward delete the original separation edges.

Hi yes I tried this… which could have worked if I was a single tile but I am dealing with a diamond net so it is very difficult to do this!

My olde plugin “Latticeizer” can do it if you group the geometry…

Get it from here [a free membership is readily available, if you read the first two lines of the Register page and click the appropriate link…]

If you want a wider outer edge ‘came’ you just need to offset those perimeter edges first…