In order to learn how to use Unreal Engine, we were tasked with building a Cornell Box. This assignment overlapped with a final project in Intro to Physical Computing (p-comp). For that class, I had decided to explore color subtraction. For this, I would set up red, green and blue lights to shine on red, green and blue objects or characters, and the play with its effect to create a sense of mystery, exploration and motion.

I realized that a Cornell Box in Unreal would give a great opportunity to both play around with this concept digitally, but also to refine the idea for the physical box with tool which required less labor than its physical manifestation.

Here is the write-up of my process of the physical box for p-comp.

Here is a sketch of the p-comp project, which I want to explore with my Cornell Box in Unreal:

The triangles are a trio of red, green and blue LEDs lights. The bar labeled with the number 6 is a bar of light.

In Unreal, I want to experiment with the position of lights, to see how their different angles play with the shapes and shadows of an object. I want to play around with a peephole, so that the user can only see some of the inside of the box at a time. Finally, I think that the transition between red, green and blue lights could have an interesting effect and motion quality to it, so animating some of this in Unreal is another aspect that I want to explore.

Here is my first attempt at building this in Unreal:

Turning off one or more of the lightbulbs created intriguing shadows and gave the start of the color subtraction effect I was after, adding another box brush plane to block the lightbulbs to investigate how this would affect the viewer's perspective.

I eventually aligned the lightbulbs into one spot, which gave the desired white light I was after. I also brought the balls closer and aligned their X, Y and Z positions.

The color subtraction effect continued to be interesting to explore in this configuration.

Slightly more green light, with red and blue lights turned on as well.

Only green light. Red and blue light are turned off.

Only red and blue lights. Green light is turned off.

Only red light. Green and blue lights are turned off.

Above you can see that when one or more of the three lights is turned off, its correspondingly-colored sphere appears black, while the spheres corresponding to the light which is turned on do show color.