Modular level design is a method designers use to quickly prototype and build levels in video games. Level design takes time, especially for games that have a lot of content. Modular level design enables teams both small and large to cut down on production time and cost without sacrificing the scale or detail of each level. Yet, it’s possible to get modular level design wrong, leading to boring player experiences and a lack of engagement.
Modular level kits are what designers use to build levels. Kits enable small studios to build the huge worlds typical of AAA games. A few designers build kits from scratch with modeling software, but they’re available in several video game asset stores, too. Read on to understand what modular level design is, how it benefits level designers, what a modular unit of functionality is, what modular kit level design entails, and where to find modular level design assets.
What is the definition of modular level design?
The definition of modular level design is a design approach that focuses on reusing a library of interchangeable components, such as walls, corridors, and props, to create new environments. Key features of modular level design include reusability and efficiency, independent creation, interchangeability, performance optimization, and grid-based snapping. The main advantages of using modular level design are production speed, rapid iteration, scalability, and support from an increasingly active modding community.
Reusability is a key feature of modular level design. 3D assets such as walls, floors, doors, trees, and other props are able to be repurposed to build different types of environments. The goal is to vary the reused assets enough that players don’t realize they’ve walked past the same wall several times. Layering on different textures or decorating the assets with props, or vegetation for outdoor environments, are just a few ways to add variation. When the same assets are used, designers are able to make large-scale environments without impacting performance.
Modular level design uses models that are able to be independently created and altered before assembly. Each component of a module is either made in modeling software, such as Maya, or bought from an asset store. Designers are able to change the component’s appearance or size without impacting the module as a whole, such as by making one wall smaller than the others in the model.
A key reason designers adopt modular level design is its reduced impact on performance, enabling them to keep the game optimized. When hundreds of different models are used in a game, the performance takes a hit since the platform has to render each of them. Each asset has different data that the platform needs to access. Using modular models means the platform has significantly less data to parse, leaving more processing power to handle the rest of the game.
Grid-based snapping is one of modular level design’s key features. Modular pieces snap to a grid system in game engines, meaning that the model loads into a game scene at a specific point and angle. Grid-based snapping is vital for ensuring that the model aligns perfectly within the world (and definitely doesn’t load beneath the level or high in the sky). In the worst cases, the model risks falling apart since it doesn’t have any assigned pivot or attachment points.
Modular level design’s impact on production speed is one of its biggest advantages. Traditional level design methods have designers planning out each model piece from scratch. This approach requires a lot of time, especially when designers are trying to make every wall in a building appear unique from others. Modular level design allows designers to populate levels without having to model every piece individually. Being able to reuse premade modular pieces speeds up production, letting designers build huge levels without eating up too much development time.
Rapid iteration is made easier with modular level design. When a non-modular model isn’t working as intended, fixing it requires examining each individual part, making adjustments, then putting it all back together again. Modular level design allows designers to quickly rearrange, cut, change the size, and test the model. The nature of modular design lets designers quickly reach the prototype stage, too, which further reduces the iteration time since they’re able to test sooner and faster.
Modular level design enables designers to scale their levels. Once designers make a modular set, they’re able to combine the pieces in endless ways across any number of levels. Designers only need to make the set once before focusing all their attention on building the levels themselves. Bigger and more in-depth levels become possible since it takes much less time to create the assets.
Making mods for games becomes easier with modular level design. Not every studio appreciates modders, but a number of players enjoy the extra content that modders bring to a game. When modding communities gain access to a game with modular kits, they’re able to easily create new content that encourages players to keep playing the game. Modders don’t have to import new models; all the assets they need are there from the start. Modding communities benefit the game by increasing its lifespan.
What is a modular unit of functionality in high level design?
A modular unit of functionality in high level design is a self-contained feature or system component that has a clear purpose, defined inputs and outputs, and few dependencies on other parts of the game. Key features of a modular unit of functionality include reusability, independence, and improved maintainability.
A modular unit of functionality is a part of a wider modular unit. When designing a building, a modular unit of functionality is a piece of that building. A piece such as a door serves the clear purpose of being an entry and exit point for the player, with a defined input and output of interaction. The piece doesn’t impact other elements of the game, such as rolling an inventory table or causing the weather to change in a level. Designers are able to take that door and use it with other modules.
A key feature of a modular unit of functionality is its reusability. The same component or part of an asset is able to be reused with other assets without needing to significantly change anything about the component. A door is able to be used across several different models, which means designers don’t have to waste time making unique doors for every building in the game. The benefit of reusing modular units of functionality is that it saves development time.
Modular units of functionality are independent from other assets and systems, meaning that designers are able to quickly develop, iterate, and replace them without breaking the entire model or system. A door that doesn’t fit in a doorway is able to be quickly resized to fit, without impacting doors of the same type in other buildings.
Modular units of functionality are easy to maintain and debug because they’re isolated. When a door isn’t opening correctly, a developer is able to remove and debug the door without the whole building breaking in the process. The developer then updates the logic for the door and makes it functional quickly by tracing the bug to the door’s code. If the door’s code were part of the building’s code, it’d take longer to find the bug.
What is modular kit level design?
Modular kit level design focuses on using a library of 3D assets, such as walls, doors, floors, props, and ramps, that snap together seamlessly on a grid. Key aspects of modular kit level design include using prefabricated, grid-based assets, efficiency, scalability, and being divided into components. Faster development, early iteration opportunities, and scope management are among the many benefits of using modular kit level design. The disadvantages include repetitive assets, rigid design, and upfront time investment.
Designers plan prefabricated assets for the level, then artists make 3D or 2D models out of them. The prefabricated assets have the same visual style, so they fit seamlessly together and in the game world. Each asset shares the same pivot point to ensure the module snaps to the game engine’s grid. Kits rely on a 3D grid to ensure that all of the module’s components, such as its floors, walls, and ceilings, line up.
The use of modular kit level design enables designers to become efficient. Since they’re reusing the same pieces multiple times, designers are able to quickly build, iterate, and populate a game’s level. With shorter production times, the cost of production is lower, too. Modular level kits are able to be scaled as a level demands, allowing designers to create huge outdoor environments or dense city blocks. The kits are able to be connected together to create large buildings, small cabins, or even narrow corridors and passageways.
Modular level kits are made up of different game components, such as 3D tilesets, meshes of floors, doors, walls, pillars, and even whole shells. Designers are able to use these elements and assemble them together as needed to create varied and detailed scenes quickly. The more components that are made, the more modules designers are able to make out of them. Creating components takes the most time when making modular kits.
One of the benefits of using modular kit level design is that it speeds up development time. Reusing a kit of assets that easily snap together lets small teams build huge worlds and games with a lot of content. As an example, I worked with an artist, and we were given the task to set up a modular kit. It took two months to put the kit together, and we were able to work with other developers, such as those handling character movement and combat, to ensure that the kit matched up with their metrics. The end result enabled us to quickly block the level out and completed the game’s levels a month ahead of schedule.
Modular level kits allow designers to iterate levels early in development. Once the kit is ready, designers are able to build their levels and have a working prototype that’s ready to iterate. Kits enable designers to see how the performance is affected, too, scaling back or amplifying levels as needed to keep the game running smoothly.
The scalability of modular level kits allows huge worlds, such as those on the scale of Bethesda’s titles, to be built quickly. Large worlds take time to make, both due to creating art for all the assets, and to playtest. When a kit is used, it helps the team keep the game in scope. There’s less risk of blowing the budget on the game’s levels, which means the extra savings in the budget is usable elsewhere in the game.
Modular kits have their drawbacks, such as risking a repetitive aesthetic in a game. When pre-fabricated assets are overly used without much variation, players start to pick up on just how same the level looks. When everything looks the same, players become bored and disengage with the content. Designers need to avoid this pitfall by not leaning into a cookie-cutter approach of kitbashing.
Using modular kits comes with a reliance on grid-snapping, which means it’s challenging to have organic shapes. Curves are difficult to snap to a grid, which impacts how architecture looks in a level. With the grid limiting design choices and layouts, designers aren’t given as much freedom to build the type of levels they want. To avoid this, designers are able to use modular kits to take care of grid-friendly assets, while handmaking assets that don’t snap to a grid for organic and curved shapes. The hybrid approach speeds up production time while still allowing designers to make organic and unique models to create interesting levels.
Although modular kits save development time in the long run, they have a hefty upfront time investment. Building a kit takes time, especially for teams that want a lot of varied options. The more complex the game is, to the point where systems impact kit assets, the more time it takes to finalize kits. Teams need to understand that while there is an upfront cost to making kits, the overall level development time is reduced, provided the process is managed well. To manage the process well, designers must have a clear vision of the type of models they need for their levels and how they appear. Making sketches on paper is a cheap and effective way of ensuring everyone understands the vision for the models in the level.
Where to find modular level design assets?
Find modular level design assets at the Unity Asset Store, Unreal Engine Marketplace, itch.io, and Synty Store. When shopping for modular level design assets, keep in mind that the assets must snap together, have proper pivot placement, have tiling textures, and contain solid box geometry.
The Unity Asset store has both free and purchasable modular level design assets that come in kits and standalone modules. Designers are able to search for assets individually or by themes, such as a starter pack or a medieval village. The Unity engine’s MAST tool makes it easier to use modular assets by ensuring that models brought into a level are correctly pivoted and snap to the grid successfully. Designers need to check that modules bought outside of the Unity Asset store are compatible with MAST when developing games in Unity.
The Unreal Engine Marketplace, now called Fab, contains a massive selection of modular assets. Its modular kits are designed to work for Unreal Engine 4 and 5 as well as third-parties, such as Fortnite. Unreal Engine regularly runs sales and provides free assets to everyone each month, allowing designers to build a large library of modular assets for free over time. While designers are able to find other free modular assets in the store, most kits are purchasable.
Itch.io is known for its support of the indie game industry, providing numerous 3D modular assets that give indie devs a chance to make games that are otherwise out of their budget. The modular assets found on Itch.io are typically low-poly and stylized. Many of its free options come from Quaternius and Kay Lousberg, also known as KayKit. When using modular assets from itch.io, ensure that they match the game’s visual theme and are compatible with the engine being used.
The Synty Store specializes in providing low-poly modular assets that belong to a theme, such as an urban city. The assets are made to work in Unity, Godot, and Unreal Engine, although a few assets only support one engine. Synty sells kits and prefabs, so designers must double-check to ensure they’re buying kits. Prefabs on Synty often require designers to do the snapping and pivot functionality themselves, which eats into development time.
Designers must consider whether the modular kit has snapping, pivot points, tiling textures and solid box geometry already implemented before buying it. Snapping ensures that all pieces in a level fit together perfectly. Without snapping, designers need to spend time creating that logic themselves. Pivot points are a critical feature, too. Designers must check that the pivot point placement is correct, otherwise rotating the modules in a game scene becomes messy.
The texture method is the final consideration when choosing modular kit assets. Tiling textures or trim sheets are efficient choices for texturing modular assets. Geometry is important, too, as it ensures that collision and other geometry-based logic functions as required. Solid box geometry is preferred over single planes as it leads to fewer errors when light is shone down on the module. Single planes come with gaps when not aligned correctly, causing light to leak into a room or building when it doesn’t make sense to.
