Tutorials using Stroke Opacity
Fades an element’s outline from a percentage — an isolated branch that is still on the drawing.
What Stroke Opacity does
Fade an element’s outline from a number given as a percentage: 100 is fully drawn, 0 is invisible.
Its natural home is pipework and anything else made of lines. A branch that is isolated, a header that is out of service, a route that is not selected — fading the stroke says the line exists and is not carrying anything, which hiding it cannot say. A pipe that disappears makes the drawing wrong; the pipe is still bolted to the wall.
Around 20 is usually the useful value for “present but not in service”. Low enough to drop out of the eye’s first pass, high enough that someone looking for it finds it. Try zero once in Simulate so you know what it costs — the line goes completely, and that is rarely what you meant.
It is the twin of Fill Opacity and the two are independent, so a shape can keep a solid outline while its interior fades, or the other way round.
