"Suburban Alley"
- a smog-filled evening
in the lonely streets of an
industrial city.

Concept

My first ideas for an image consisted of some low-poly to high-poly scene transitions or pixel art designs. However, I wanted to challenge myself to generate a more realistic-looking image of an everyday scenery. That is why I decided to model a street alley.
At first, I was undecided, whether the scene should be rather inviting and cozy-looking with a little cafe in the sunshine or rather dark and uncomfortable.
When building up the initial elements of the scene, namely the car, dumpster and anterior street lamp, I just added very few light sources, such that my models were visible. I liked the dark aesthetic of the first images, so I kept this theme.

 

Next, the two houses in the front were added. I used the same model for both houses to bring out the monotony of a suburban area with systematically build residential districts. As the buildings do not look too modern, I decided not to use a tarred street, but went with cobblestone instead. The cobblestone also conveys the feeling of a small alley better.

Initially, I planned to build a dead street end. However, it felt like three connected house walls would have made the scene too restricted and I would not have been able to show any more of the environment - such as the sky - to put the scene into context.
Hence, I added a larger street from which the alley is forking off. I made the main road look wider, changed the street material and later on decided to add a bus station, as well as the stop sign.

Sky

At first, my idea was to use a dark night sky for the scene. However, I quickly decided that a black sky was too boring. When I experimented with different constant sky colors, the concept of a dusty sky with orange glow appealed to me.

 

However, constant colors did neither look realistic, nor pleasing. That is why I decided to use an image texture. The texture was mapped onto two large triangles such that it could fill the whole sky, without any need for repeating the texture, which otherwise lead to undesired edges.
The image texture also introduced an additional lightsource, visible in the lower left corner of the sky. Its position was considered in the placement of lights in my ray-tracer as described below.

Lighting

It was quite a challenge to set the lighting of the scene to fit a dark alley, but to also have enough details visible. I wanted the image to convey the feeling of a dull suburban area under a sky filled with smog from the nearby city and factories. Additionally, the color of the sky had to match the tones of the overall lighting to make the scene appear realistic.
I started working on the light emitted from the four streetlamps, where a combination of a spot- and point light was used. Initially, all lamps emitted pure white light. However, this gave the image an artificial looking appearance, as the color was too cold and did not fit the smoggy sky aesthetic. Hence, looked up some common RGB emission values for street lamps and settled with a warmer, yellow tone.
At first, I also added some directional lights in a yellow-rosy color to light the objects up a bit more. However, these lights caused additional shadows that I considered too harsh.

 

When adapting the directional light to not cast any shadows, the brightness level seemed too artificial and shadows were barely visible anymore. Hence, I decided to only use the streetlamps as light source, increased their radius, as well as intensity.
By removing the directional lights, the upper half of each house was very dark, which was not realistic considering the sky lighting and the real-world global illumination.

 

That is why a point light in an orange-pinkish color was added. This light is supposed to mimic the illumination coming from the sky’s light source, which is just slightly visible on the lower left part of the sky: the right house is partly illuminated by it, whereas the rear building – back-facing this light – is not lit additionally.
To further counteract the darkness, and to imitate global illumination, each object was additionally assigned a small level of self emission.