I wondered is there an option to make a dashed line in Sketch mode render? Looked around for this, but never could find a solution. Generally the idea was to show certain volume that stand above the cutaway planes (roof window, upper-floor balcony, roof borderline etc.) I usually add it manually in other graphic software, but hey, I'd applause if someone smarter than me uncovered it.
You can use instead of Sketch render 3D document. It gives very good and clear view (from any angle) to the model.
If you really want to have sketchy look - you can apply graphic override to the model and choose hand drawn line type. As well as choose dashed lines for particular parts.
Don't forget, that you can use annotation tools in 3D documents - like dimensions and labels, have different results using fills and colours, also shadows.