PRODUCTION LOG 10

LIGHTING

I have always found it difficult working on lighting, in a 3D environment, so I tried to keep refining it throughout the entire process. The aim with lighting in my environment was to focus on the key areas that I planned to work on (Hydroponics, Med Bay, and Command Centre), hence the contrast of purples, warm whites, and blues. Since I had also gone with different lighting setups in the scene, there was a lot of experimenting with values and colours to get the look I was aiming for. For some of the light actors in the engine I refrained from changing their colours as they made things look too artificial, so instead, I stuck to changing the temperature of the lights.

When it comes to lighting my scene, I used Unreal's Environment Light Mixer which allowed me to add everything I needed to properly light the scene. Working on an interior environment, I had to carefully plan the lighting setup and also consider the impact that lights have on performance in games. My projects consists of creating a 3D environment and somehow I have the liberty to add as many lights as I need to, but at the same time, I want to make a well balanced environment, appealing and optimised.   

LIGHTING SETUP

In my environment, I used all types of light actors available in Unreal. 

Points lights

Point lights have probably been the most used throughout my environment because they are a good choice for localised lighting sources, such as ceiling fixtures, and also to provide general illumination. For these lights, I adjusted intensity, attenuation radius, and colour temperature (slightly) to match the intended atmosphere of each area. To reduce their impact on the performance, due to high number of instance, I set most of them as static and disabled shadows (for those used specifically to illuminate darker spots).

The area that uses point lights heavily is the Hydroponics. This is because of many grow lights placed in the room. The grow lights are basically lighting fixtures models that have applied emissive materials to the tubes. However, to further enhance the fluorescent tubes glow, I added additional point lights, with the same colour to match the emissive one.

Spots lights

Spot lights have been used for a different lighting fixture (for walls) and mostly to simulate focused light, such as stage light or lamps. These lights emit light in a specific direction, usually in form of cone-shaped beam, with the intensity of the light falling off gradually as it moves away from the centre of the beam, which makes them perfect for light projectors and desk lamps.

Rect lights

Rect lights have been used mostly for ceiling lighting fixture. These lights have specific size and emit light from a surface rather than a single point, usually a rectangular. They are perfect for simulating light sources that have rectangular areas, such as screens, light panels, and ceiling light fixtures. Area lights have two key features, the source width and height, both determining the size of the surface (rectangle) along its local Y and Z axis, from which the light is emitted. This is helpful for creating various lighting effects as seen in the pictures below.

Directional light

Initially, a directional light was used in my environment to simulate sunlight coming through the opening in the ceiling. However, this caused some issues with light leaks and decided to change it into a spot light with increased intensity which eventually proved to be a more efficient approach. Having a directional light for that only purpose was not worth it, as it also has a great impact on performance.  

Lighting effects

To create some nice lighting effects such as intense glowing or bloom, I tweaked each setting for the light actors that were places in the areas where I wanted to apply such effects. In order to achieve this, there are several steps to take. First, exponential height fog must be added in the environment, as this intensify the effect. Then, in the detail panel of the light actor, the value of the Volumetric Scattering Intensity must be increased until the desired look is achieved. I think values between 3-5 are good enough in my case.

To make it easier when working on lighting and to keep a good consistency in lighting setup and colours, I added my colours picks in the colour gradient tool.

POST-PROCESSING

Another crucial aspect of the overall feel of an environment is how we perceive it through camera. Adding a post-process volume in the scene, set to infinite extent (unbound), I could fine tune how everything is rendered by the camera. With lighting being a key part of my environment and relying on it to create specific mood and atmosphere, there was no need for much post-processing effects, but I used it mostly to adjust things such as exposure, temperature, and colour grading.  

Exposure was one of the first thing I changed in the post-processing volume. As I watched many lighting tutorials, I noticed that many artists do so and recommend it, just because you can have more control with a manual exposure, instead of relying on the automatic exposure. Unreal Engine, sometimes, makes interior environments look too bright which also creates some lighting artefacts.

I set the metering mode to manual and the exposure compensation to 4. Also, I disabled the physical camera exposure. Additionally, I tweaked the settings for the local exposure which reduces the contrast for highlights and shadows.

Another change in the post-processing was the colour grading. Here I set the temperature type to Colour and the value to 5000. Additionally, I slightly increased the value of the Saturation to 1.3 and decreased the value for Contrast to 0.95. 

One thing that I experimented with was colour LUT in Misc options. LUT colour grading are used to remap the the colours in a video or 3D scene. It's like a translator, converting the original hues and tones into a new colour space.

LUT scenarios: Afternoon, Morning, and Night (left to right)