Design Diary: Volumetric Lighting Techniques

I’m fascinated by lighting, illumination, and colour… since starting my pathway into the games industry, it’s been a struggle to pinpoint what it is I’m truly passionate about, and what this industry can offer me to better pursue my passions.

Game development allows me the freedom and space to experiment with lighting in a relatively seamless way, and allows me total control and creative freedom over the light source, something that doesn’t come so easily in other professions.

Recently I’ve been working on a new project that utilizes lighting and illumination in a way that directly effects game play. This blog is going to be a bit “half and half”; half will be about what I’ve been working on for ‘Project: Illumination’ and the other half will be talking about the lighting processes I’ve learnt in the past six months and how I’ve implemented them into my lighting design practices.

volLighting - Example

To prime you for what this blog is going to be about, I’ll outline what volumetric lighting  is, and its uses in CG lighting.

Essentially it’s a technique widely used in 3D computer graphics to add lighting effects to a rendered scene. It’s highly probable that those of you reading this, that have played a variety of video games which include an exterior and interior environment, have witnessed this technique for yourselves…

It allows the viewer to see beams of light shining through various environments, or from a variety of sources in the game world; seeing sunbeams streaming through an open window is an example of volumetric lighting, but this is also known as crepuscular rays.

 

Some lighting tips and tricks, I’ve picked up along the way…

Note: The things I’ll be discussing throughout this segment are tips and tricks that I employed when working on ‘Project: Illumination’, this is a side project that I’m currently working on where the core mechanic is light. 

I’ve been performing some research tasks into the theory and application of light, both in the practical sense and through CG environments. What I’ve learnt is that photography can be a great method of understanding the practical application of light sources. As a research task into my lighting design for Project: Illumination’, I video recorded and photographed light sources in and around my home, that were relevant to the type of lighting that I was going to be designing for my game.

Another useful application of this method is to understand exactly how these different types of light sources (in the practical world) light up the environments they’re a part of, which I saw as an equally important insight for my designs. Below you can watch my ‘Lighting – External Research’ footage for a street light located on my street.

I recorded the video from a first person perspective (holding the camera landscape in front of my eyes), which is the same perspective as the player camera in my game. This enabled me with the ability to quite literally step into the role of the character (not to be confused with the player of the game) in my game, allowing me a better understanding of how this light source when it’s in the CG environment, should be acting and reacting to the character.

Additionally, being able to “re-enact” these elements of the game in the real world, opened up a whole new viewpoint for my lighting design practices. I’ve had first hand experience of how these light sources worked when I interacted with them in the real world, which equipped me with a heightened level of knowledge of the source material, and an increased ability of translating those experiences I had into the game world effectively.

Furthermore, from conducting this research into my source material, I was able to better understand and visualize the elements of volumetric lighting that I was wanting to implement in the game. Below you can see four sequenced photographs of the same light source with differing amounts of glow radius presented, and the distance that the visible light travels before it becomes invisible to the naked eye. To better understand what I’m talking about here, try focusing more on the visible light around the central light source.

I wanted to really mess around with this component of volumetric lighting in my game. I wanted the ability to adjust the amount of light that travels from light sources, that is still visible to the player, and have total control. This would in turn allow me to make this highly visualized and artistic aesthetic for the lighting in my game.

This meant that I would have to cheat practical application of the source and disregard almost all of the technical factors I’ve learnt about light sources and their uses in the real world, but it was all for the sake of art, so it was a necessary sacrifice to achieve my vision and one that I was willing to make.

quantum-break-vol-lighting
Screenshot: Volumetric Lighting is used throughout ‘Quantum Break’.

Jumping back to my primer for this blog post when I stated that “you’ve probably seen this method used in other games…”, I wasn’t lying about that… pretty much any third person shooter/ action adventure game, open world role playing game, and majority of the first person shooter market use volumetric lighting at some stage in their game. It’s a widely practiced lighting technique for achieving god rays/ sun shafts, interior and exterior lighting for windows and open door ways and for a variety of other uses. Demonstrated in the above screenshots of Remedy’s ‘Quantum Break’ and below in Ready At Dawn’s ‘The Order: 1886’, volumetric lighting is used to achieve exterior light protruding through into their interior environments.

order-screenshot
Screenshot: Volumetric Lighting is used throughout ‘The Order: 1886’.

I looked at a range of games to gather inspiration of how I could use volumetric lighting in interesting ways, and to also see how it had been used in other video games and to what extent. I referenced a lot of realistic uses of this lighting technique, as demonstrated in the video below from Naughty Dog’s ‘Uncharted 4: A Thief’s End’ and likewise, in the above screenshots, where this technique was used to mimic the effects of exterior light from a global source (predominantly the sun/ moon) when it enters through interior environments.

 Designing for ‘Project: Illumination’

I wanted this game to be something different, something unique. ‘Project: Illumination’ was going to be centralized around the core game mechanic of light, and how that effects players and creates dynamic game play.

This project is an exploration into many things, but predominantly exploring lighting design and how that can help me best represent nyctophobia and claustrophobia through the medium I was aiming at portraying them through; a video game.

Lighting is a major component of ‘Project: Illumination’. The game centralizes on points within the world which are depicted as being “safe havens” for the player. These are the points that the player should want to be reaching, so they should be equally “attractive” and visually apparent to the player so that they’re then drawn to them.

In the below video you can see the current state of my game, which accurately depicts this idea of a completely blackened space that has been overcome by darkness, where there is a scattering of these “safe havens” that are demonstrating safety in this dark world, and shows the player working their way through this navigable space…

Additionally demonstrated through the video above, these “safe havens” will become less apparent and harder to locate within the game world the deeper you get. I feel that this video clearly represents my methodology behind my lighting design on this project, and the artistic and aesthetic approach that this technique of CG lighting is allowing me to achieve.

The above screenshots show-off these lights with different colour variations, additionally the amounts/ and values of the lighting effects that are present on each source are noticeably different. I’m achieving this through the use of ray marching (also known as Volume Ray Casting) from each of the light sources to manually adjust the volume and the amount of scattering from the source, the extinction of that scatter, and finally the sample count of the effect on the source, which is allowing me to achieve this “balloon/ bubble” like visual.

This technique is similar to the one used in many of Guerrilla Games titles, specifically ‘Killzone: Shadow Fall’ and more recently ‘Horizon Zero Dawn’… where the former is explained through in thorough detail in the publication: GPU Pro 5: Advanced Rendering Techniques by Nathan Vos.

volTest_6
This is what ‘Project: Illumination’ looks like before I’ve blackened the scene using a variety of Image and Lighting effects, particularly ‘Edge Detection’ and ‘Contrast Enhance’.

If you’ve played Remedy’s ‘Alan Wake’ then you’ll probably be drawing some similar design choices as the “safe havens” throughout that game and mine, and so you should be… it’s no secret that my designs have been heavily inspired by how those light sources work in that particular game, and how they create a unique dynamic between “light and dark”.

alan-wake-reference
Safe Havens are marked out in ‘Alan Wake’ via these identifiable street lamps.

By following along a similar deign path as the “light and dark” dynamic demonstrated through ‘Alan Wake’, I believe that this will be an effective way of portraying nyctophobia and claustrophobia through a video game, and particularly through dynamic game play.

alan_wake_safe_haven
Screenshot: Alan Wake moves towards a safe haven in game, these are safe spots within the game world.

To wrap up this lengthy discussion into lighting design and my practice, I’d like to share some closing thoughts on this project and the CG lighting techniques that I’ve employed, in order to create an experience that correctly and effectively depicts the effects of two widely occurring phobias.

This discussion is a demonstration of my work; a deep dive into my personal design theory behind CG lighting and its abilities in conveying complex feelings and emotions through a virtual world. I think it’s amazing how this component of video game development, that is essential in bringing your scenes and ideas to life, can be utilized and designed in a array of different ways to directly convey a particular tone, experience, and meaning to your game for the player. The ability to show users the power of this digital medium in new and interesting ways which is not possible in other creative platforms is a blessing.

Thanks for reading!

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