Lighting Breakdown – The Shield
In this blog post I briefly break down the basics of the lighting for the shield scene, done in Unreal Engine. So, the first thing was putting out the main key light, which in this case was coming from outside of the cave. Similar but dimmer version were added backwards to light up the background using the outside as the source.
Because it is very blue main key light, it is a general good idea to balance it out with some warm. To do that I created fire sources outside of the image and aimed it on the shield, surrounding walls and such to fill in the shadows with warm light. I also used skylight to fill in the shadows everywhere with some colour.
I then added more point lights, and these were baked rather than real time. This was to fill in the cave with a mix of orange and blue, and have it transition more around to avoid harsh transitions.
Because I was using skylight and baking, and the surroundings were not reflecting as intended, I added what I was missing: Reflection Spheres. This created the reflection that would occur in such a wet environment.
Which brings us to the important part of this lighting setup. The fog. It is important to understand that fog is really water particles. And light slows down when it hits dense objects like glass or water, which in return creates refraction, which spreads the light everywhere and makes it diffused. That is the simple explanation. So here is a quick example below. Originally explains how rainbow is made, but the principles are similar for our purpose. The light hits the hovering water particles in a fog, it comes back out somewhere else, and also different colour. In our case we have less white and more blue/orange. And the light we want to turn into fog, is the main key light which is blue. On a side note, that is also why you see that things are somewhere else when in water, because the lights slows down, bends what we see and shows a different position of a fish or a pencil in a glass etc.
Anyway, that is why you see fog a lot in concept art, backgrounds in movies and otherwise as it helps light up the scene evenly in a intelligent way. So you end up with this:
The main reason I created this scene was to understand the fog and volumetric settings better, so this scene will probably receive an update in the future unless I make a new scene to replace this. But as you see, the dark cave now becomes lit due toe the fog picking up the light sources, and spreading out more diffused rather than specifically on the spots.
Below are the settings used to get the look, and it can still get better.
Key light settings
Fog Settings 1
Fog Settings 2
So, hopefully you learned something new.
Summary:
The general idea is to understand that light behaves different in the environments, and keeping the ratio between each light fairly different. Like, the key light is at 4K intensity and 8500 temperature color following Kelvin scale. This means that the other lights are less in intensity and has another color temperature to create the atmosphere, depth, feeling and environment.
We also need to add in extra lights to fill in the shadow, and help build the environment storytelling by leading the eye where we want the viewer to look.
Lastly, I did change the materials roughness/specular level and after this blog post, I changed shadow bias to deal with some of the light bleeding occurring (light reaching places it shouldn’t be).
Make sure to check up my previous blogs:
Compound Lighting Breakdown in Unity
Crunch goes to war Lighting Breakdown in Unreal
Don’t forget the skybox in Unity
Youtube:
