— update: I’m a bonehead and missed that this is an existing feature. One thing rhino doesn’t currently do is allow users to lighten, rather than darken, edges. That’s my new feature request.
Currently view options allow for surface and polysurface edges to be made a uniform or the object color.
It would be handy to add an option where one can set them to be a certain amount darker or lighter than the object color, for example making the edges of a blue object or an object on a blue layer show up as a lighter shade of blue.
In 2d viewports, it can be hard to see object edges when they’re the same color as the object, but changing all edges to a single color is both a little too aggressive of a solution and it also eliminates a color from the user’s useful color options: for example if I make all edges white, using a white layer to draw guide lines is no longer a good idea.