Robert,
You may not have noticed that I am on 12.5.2, so your .vwx file doesn't work for me.
But it sounds like to answer to my question is "no." You described a method for using double layered viewports and adding light sources, but what I wanted is just plain horizontal siding lines on my walls using hidden line rendering.
Here are two example images, first showing hidden line rendering, which I would like to also show horizontal siding lines, just as the roof hatch shows the shingles. The next is an OpenGL of the same model. Is there a way to get my siding lines on my walls using just hidden line rendering, or is Robert's suggested method the only way?
Thanks