hi,

say i have some arbitrary path. for example: https://postimg.cc/q6Tbm2rt

how can i make it be like this https://postimg.cc/V5wPZCDB ?

TNX

Maybe this:
http://tavmjong.free.fr/INKSCAPE/MANUAL/html/Attributes-Stroke.html#Attributes-Stroke-Complex

The problem with using clones is that the wider path is distributed right ans left of the smaller one.

To achieve the look you want, I'd set a thick stroke, duplicate and convert stroke to path, then remove the left part of the outline.

Another way is using Offset LPE : 

• clone the path (Alt + D)
• select the clone with object's panel (Ctrl + shift + L), then open Live Path Effects (LPE) (ctrl + &) panel and apply it an Offset LPE If the original stroke is, let'say, 4 mm, use a 2 mm offset.
• During this process, you can see in LPE's panel that the cloning process as been transformed in a Clone Original LPE (just on top of offset LPE) : click on it, and in the attributes TextField, remove "style," and click on the tick icon right to this textfield, so that you can set a different stroke width and color.
• Now you can select the original with object's panel and if needed modify it with node tool : the "clone" will follow.

Here's another method.

Duplicate the initial path [ctrl+d]. Set the stroke colour. Increase the stroke width. Send to back.
Duplicate again. Use the Bezier Pen tool [b] to close the path. Fill and no stroke.
Select the lower two paths (grey & orange). Stroke to path.
Select all three paths. [Path > Flatten] or [shift+f].

tnx,

i think @David248 answer is best for me.

is there a way to make it a "macro" so all those steps will be applied in a single click?

**answer to myself: write extension**