Week 8 - Monday: LOD Test

Level of Detail or LOD, is a method for simplifying the geometry of a mesh so that the game engine requires less resources to display it in-game. A common use of this is to display a large array of assets on screen at once without a severe hit to the games performance. The LOD will progressively raise or lower the detail of the assets relative to the player's proximity to them. If done effectively the reduced visual quality of the models will often go unnoticed. A noteworthy example of this would be the 2017 game The Legend of Zelda: The Breath of the Wild, in which a vast landscape is fully open for the player to explore.

The Legend of Zelda: Breath of the Wild (2017) uses LOD's to display the vast kingdom of Hyrule that loads in detail the closer the player gets.

Whilst I am certainly not creating anything near the scale of Hyrule, I acknowledge the importance of using Levels of Detail to boost a game's performance. I have several high poly assets that I want to reduce in size and decided to practice using LOD's on one of them. I selected my model of a Corinthian capital because it has about 10k triangles, making it a good specimen to experiment with.

 My Corinthian capital model at about 10k tri's.

I had two options for creating LOD's for this model. I could either use 3DS Max and manually create lower resolution versions of the model, or I could use the in-built LOD feature within Unreal Engine. I chose to use Unreal Engine as I was able to provide a better representation of the technique in action, which you can see in the animation below:

 Here you can see the result of applying different LOD's. Ideally they would be applied the further away from the camera they are, but to better illustrate my results I have manually toggled them on. Notice how drastically the triangle count drops in the top left of the screen per LOD.

I intend to apply LOD's to some of the higher density assets that I have in my scene. I think anything above 5K triangles that will be repeated en masse should have at least one LOD. As I am creating a smaller scale environment I can get away with not using LOD's on a lot of geometry. That being said, I intend to use LOD's to straight up halve the amount of triangles on some assets as the effect is almost unnoticeable from a distance. For the Corinthian capital I will limit the asset to two LOD's as the geometry starts to look very jagged from LOD 2 onwards.

Using LOD's in my environment is important to show that it is fit for purpose as a fully functional game environment within Unreal Engine.

NINTENDO. (2017) The Legend of Zelda: Breath of the Wild. [CARTRIDGE] Nintendo Switch. Kyoto: Nintendo

UNREAL ENGINE. (2018) Creating and Using LODs. [Online] Available from: https://docs.unrealengine.com/en-us/Engine/Content/Types/StaticMeshes/HowTo/LODs [Accessed: 9th July 2018]