I think I saw someone doing something similar some time ago (on youtube), but I don’t know how. Maybe he used some plugins, or I have an incorrect memory.
I tried the “skin”-modifier, but the result was not what I need (not scaleable and at the crossroads it was thinner than on the other parts). Currently the line is a normal mesh (vertecies that are connected, not a path). But I can make it a path if that is required.
Thank you both a lot. Both variants look very helpful. I will stick with the script for this one, but the curve variant may help me at another topic. Since I only used blender for character modelling in the past I was not familiar with curves/paths and what they can do