Why are games so big?

One of our most asked questions as game developers is a simple one. Why are games so big? Game sizes have been increasing rapidly over the last few years and they won’t be stopping any time soon. It was only back in the days of the Xbox 360 that games consoles came with hard drives as small as 60GB or even 20GB. These days that couldn’t hold a single AAA game with the likes of Gears of War 4 taking up more than 100GB of space. So why is this?

The short answer is art. Whilst there are a great many things that affect a game’s overall size the majority of it will come from the 3D art required in games. The models themselves take up some space but the majority of the size comes from textures.

Art In Games

As technology advances at a fantastic rate, artists are pushed to keep up with the times. Even if you don’t believe that art is an important part of a game the teams must keep up with advancements in monitors and TVs.

As the resolutions get bigger the art in the game has to keep up. If you use a small 256×256 pixel texture for a brick wall, like we would have done previously, and put that up on a 60 inch 4k TV all you are going to see are the pixels. For this reason, even games without photo-realistic graphics need more and more space available.

2D Vs 3D Games

This raises the question then, if the 2D textures are the part that adds all the size then why are 2D indie games like Dead Cells 570MB and many others smaller?

There are a few reasons for this, in a game like Dead Cells the player will always be viewing the game from a certain angle and a certain distance, this means it can be completely controlled what the player can see. Whilst they still have to make sure it can be played on the biggest TVs they know that the player won’t be running and putting the camera right up against a random wall. They can make it work for the camera and that is good enough.

Textures and Materials

That is a very specific case though and doesn’t describe every game. Games like Super Mario Maker 2 have a similar set up to Dead Cells but uses 3D assets and that comes in at 2.8GB, nearly 6x the size of Dead Cells. Another similar game is Little Big Planet 3 which comes in at a whopping 11.4GB.

To understand the reason we have to get a bit technical. 3D assets such as characters and environments have materials applied to them to give them their look. Materials are made up of a number of textures, we have an in-depth explanation over on our Modding Fundamentals page covering the topic. To simplify it, there are 2D images that control everything from the color that’s shown, to how shiny it is. They can also add surface details and control how the surface moves. This means that the material that makes up a platform in Super Mario Maker 2 could actually be made up of many different images.

You may be wondering why even if you only play games on low graphics settings the files are still so big. This is because no matter what quality you play the game at it must download the full resolution images. These are then compressed down when the computer pulls them into memory through a process known as mipmapping.

All textures are created at resolutions that are powers of 2 such as 512×512, 1024×1024, etc. One of the main reasons for this is so that they can easily be reduced at run time as no matter what size they are they can always be halved. The downside to this is every time we want to increase the quality of the texture it has to quadruple in size. As you can imagine this adds up across an entire game very quickly.

Lighting and Lightmaps

Another aspect that is not as common these days but still has its uses is something called lightmaps. This is when a game engine works out the lighting ahead of time and ‘bakes’ them down into a texture that is applied to the object. High-end consoles and PCs are much more capable of rendering real–ime lighting so these are used less and less but they are essential for games on mobiles and handhelds.

These lightmaps will need to be baked down for all the objects set to use them which is often anything that doesn’t move. In large games these can account for many GBs on their own.

This is yet another layer to apply to the end result and it’s something that most 2D games don’t use. Most 2D games have all of their details painted into the original image, maybe with it increasing or decreasing in brightness so this is not a step that applies to them.

Game Size Vs Play Time

One thing that is often confused when talking about games is the size of the game and the playtime. Going back to the example of Dead Cells it can have many hundreds of hours of gameplay in it’s 570MB whereas a game like Hellblade: Senua’s Sacrifice clocks is at over 14GB for about 8 hours of gameplay.

A large reason for this is the reuse of assets. Dead Cells has a fairly small number of levels, enemies, and weapons that are somewhat randomized, making each playthrough unique. A game like Hellblade relies much more on a strong narrative which the player works their way through in the only way possible.

This shows that the amount of time it takes to complete the game has little to do with its file size. It has much more to do with its art style.

Cutscenes

Another reason for the increase in file sizes recently is cutscenes. Much like before they constantly have to work to keep up with monitor and TV quality meaning the file sizes continue to skyrocket.

Pre-rendered cutscenes also have the frame rate to consider with many users unhappy with anything other than 60fps. This will double the file size compared to a 30fps video.

These videos are often much longer and fully voice-acted unlike they used to be in older games. Which leads us nicely on to our next point.

Audio and Voice-Acting

An area that’s often a surprise to people when talking about file size is audio. The quality of audio has increased significantly as our speakers get better and people want fully surround sound in their games. This has increased the size significantly.

Although the biggest change of all for audio is definitely the reliance on voice-acting. Unless it’s specifically within the game’s style it’s often unacceptable to not have a full voice-acted game. It would be too jarring to be midway through a highly realistic game like Mass Effect only to find half of the NPCs talk in text boxes. A great many games now rely on voice-acting of this quality as a core gameplay point.

Games Are Big

There are a great many other factors that affect the overall file size of the game but these have been some of the biggest culprits.

Some of the information is quite technical in nature and if you want to know more about any of the topics you should head over to our Modding Fundamentals page which explains the basics of how games are constructs.

Hopefully this information has given you a much better understanding of why you have to wait for hours, frustrated, while your game downloads and installs.