From a user:
sketchup linework (like parking lot striping) disappears when 'rendering'
You can set this option to render lines and edge lines:
That might work for you, especially if set a material on only the lines and edges that you want to render, and select All with material set as the choice here for Edge Lines.
Foreground Images can also be used to render the edges and text in a model that you otherwise not get rendered. See this explanation:
That can be a bit tricky, since you have to have the output image size have the same aspect ratio as the current SketchUp window, but it is interesting what you can do with the foreground image automatically created when Use Edge lines for foreground is checked.