I’m constantly scribbling loose, ugly things on notepads and whiteboards to communicate ideas, but it’s been a long, long time since I can remember actually finishing one proper. I recently picked up a shiny new Surface Pro 4, so I thought I’d end that sad streak with something fun.
For the drawing above, I tried an approach I picked up from Marc Burnet’s Drawing & Coloring Techniques tutorial. I learned a lot about 2D rendering from a compositing approach and I thought I’d share the process I used here.
I decided pretty early that I wanted to do a caricature of my son. I took this photo awhile back. It’s not the clearest photo in the world. I caught him in a blurry mid-expression but every time I see this picture I can hear him noisily rolling around the house so I wanted to try and capture some of that. On a technical level, I like that there’s a good balance of organic and hard surfaces to get my practice on.
Normally I would go straight into construction with lines but this time I started by blocking out the rough volume. On a separate layer I did a light sketch to try and find the lines. My natural inclination is to get more and more refined at this early stage which inevitably trips me up later when I’m trying to trace over my fat messy lines. This time, I tried to restrict myself to construction. When I was ready to move on, I set this layer to a very low opacity and starting doing the more final, clean lines. I went through several different facial poses and stylistic caricaturizations and finally settled on a stern expression he often sports while zipping around on his firetruck.
With clean lines established, I then started building out the render layers below it starting with the ambient occlusion pass. Normally I’d go in and try build out dark and light values from somewhere in the middle, but I tried to think about the piece in distinct render passes. The ambient occlusion pass defines the form with an inspecific light source. In general, the goal is to paint in darkness where it’s difficult for light photons to enter (ie where two surfaces meet to form creases). Instead of trying to manage all the lights in your scene, this step focuses specifically on adding dimension and form to your 2D line drawing. (For more information, here’s a great tutorial on painting AO.)
On separate layers, I also filled in flat colors for each of the major surfaces (hat, face, jacket, gloves, pants, boots, firetruck red, firetruck chrome, tires). This is the diffuse/albedo map. These layers end up also functioning as a quick selection set for later polish. When these two passes are multiplied against each other, you get a rendering that has depth and ready to be lit.
I’m not great at simulating physical light or being able to map out a mental model of the 3D scene so I decided to keep things as simple as possible by limiting the scene to just 2 main sources of light. The first is a blue atmospheric light that generally is coming from above to simulate the sky strongest on his hat, weakest as we progress to the truck. With a layer set to blending mode “screen”, I used a very large, very soft brush at a low opacity and gently wiped in gradients for any surface that appeared to be pointing up.
Next, I painted in a soft yellow key light coming from the upper left corner down to the bottom right corner of the canvas. This layer was also set to “screen”. I erased away any areas that were blocked by other elements (ie the screen right arm blocking light received by the screen right leg). Normally I would actively add shadow to the scene but this process has you subtract it from separate light passes instead.
After that, I made another layer to paint in bounce light/global illumination for color bleed like the red hat bouncing red photons to the areas on the forehead nearest to it or adding yellow to the nearby clothing or truck. The differences are subtle but with each pass they start to really add up to feel more and more rendered.
Finally, I created a separate layer set to “normal” to manually paint in any specular hot spots that I couldn’t achieve with the previous blend modes.
Lastly, I made some detail adjustments to things like the hair and eyes, pumped up the saturation on the diffuse/albedo layer, and roughed in a vague bokeh backdrop. All in all, it took me about ~5 hours over a few days. I really enjoyed this way of building up a painting and I think I’ll stick with it for future drawings. I hope you found the explanation helpful!