One of the longtime limitations of working with SketchUp in designing for film and television has been the final output of the program. As powerful as SketchUp is as a modeling tool, and as dynamic as the animations and moving sections can be, the image output from SketchUp has been limited to a shaded polygon model or one lit by a single source (the sun). Even the models lit by the sun are relatively flat and lifeless, without any change of value within the planes of light and shadow.
To overcome the limitations of the SketchUp look your choices were to import images of your model into Photoshop® or export the model to a rendering program and work on it there, both very time-consuming prospects, or using the SketchUp image as a guide to laying out hand-drawn artwork, which has probably been the most common way to
turn a SketchUp image into a final drawing.