Non-Photorealistic Digital Rendering

A client asked for non-photorealistic illustrations of four model homes for use in marketing materials. I had produced most of my previous illustrations using color pencils overlaid on black and white hand-drawn ink lines copied onto charcoal paper. Knowing that these illustrations would be subject to several modifications before final approval, I decided that to produce them digitally would allow me to change them more quickly than would drawing them by hand. Nevertheless, I decided to try to simulate the appearance of color pencil drawn over lightly drafted linework.

Because I had previously designed the homes, I could quickly and easily construct SketchUp digital models of each of them. Using a combination of SketchUp, Kerkythea, and Photoshop Elements, I was able to rapidly and affordably create a series of digital renderings.

I derived the technique largely from work done by my friend Jim Leggitt, and combined it with other experimental techniques of my own to get an appearance that satisfied both my client’s goals and my own within a very short turnaround time.

Step 1:  I created a base model in SketchUp, shown here in original form. 

Step 2:  I exported a jpeg view of the model in high resolution, 2000 dpi. This produced fine linework while preserving the textures, colors, and shadows generated in the model. I imported the jpeg into Photoshop Elements, and created a new adjustment layer so that I could fine-tune the values. Note that the people have disappeared! The client wanted to feature just the house, but allow potential buyers to imagine themselves in the picture.

Step 3:  Using the SketchUp base model, I created a photorealistic rendering in Kerkythea and saved it as a jpeg. Its only purpose was to generate appropriate reflections in the windows which SketchUp cannot do. Opening this rendering in Photoshop Elements, I cut and copied the reflections, then pasted them as a new layer over the layer created in the previous step. I set the layer to “multiply” so that the window mullions would be visible through it. I used the eraser tool to ensure that the reflections appeared to be behind the foreground elements.

Step 4:  To simulate a surface similar to textured paper, I added a layer consisting of a very light gray rectangle with a "sandstone" texture filter, and set it to “multiply”.

Step 5:  To satisfy my client’s preference, I added a very light gray layer set to 91% opacity, then using the eraser tool with a broad “sponge” brush, I erased away all but the edges to vignette the drawing and enhance the “hand-drawn” allusion.

The final product, although clearly not hand drawn, simulates some of the soft characteristics that make hand drawings so appealing, but using a more flexible, easily adjustable, rapid technique.

For more information, visit Ray Brown Urban Design or Ray Brown Studio