@x1l3nt said:
To color lines I've been using Window > Styles > edit > edges > color set to by material and then using the paint bucket tool but for some reason this is no longer working for me, I must have changed a setting or something, help would be appreciated thanks!
You may have changed scenes to one that hasn't "by material" saved. So edges are black again without noticing that you changed back the style to "edges color all the same".