Changing display colors and line weight of lines and arcs

creating visual differences in colors and line weight of lines, curves, splines and etc.

SketchUp is 3D modeller, using straight edges to create (approximate) curves to form faces … a model.
The lines (edges) does not have a weight.
You need to use layout for this kind of thigs. (I’m not an expert of it).

However in a “certain level” you can give a visual distinctiveness in SketchUp for the edges. Using the styles: applying material to edges, use section, etc. … use color by tag, different dashes for tag …

( ;; etc )