Binary Space Partitions (BSP Brushes)
Hearing “Binary Space Partitions” alone already sounds like something extremely complicated, but that would be the complete opposite. BSP is the process in which you use simple geometry to create a layout, a framework, of your level or environment. These geometric shapes are what are called “BSP brushes” within the Unreal Editor. The BSP brush is simply just a geometric shape that can be used right away inside your editor as soon as you create a new project. Essentially you uses these brushes to begin to visually see your layout for the level without having to create a single mesh, texture or material. To use these brushes within the UE4 editor you simply will click on the “Modes” tab and you will see a section that says “Geometry”. After selecting “Geometry” you will have a list of different shapes that you can simply drag and drop into your viewport and directly into your level. These brushes become simple geometric placeholders for your final meshes.
Given these different geometric shapes you can see how you can use them and reshape them and resize them to create a visual framework for your level and it can bring it all together rather quickly.
The process of beginning to use these shapes and build your “prototype” is called “Blockout”. It is the process where you begin to “block-out” your level using these BSP brushes. You begin to “box” brush to resize it and scale it to be a tall skyscraper in your level or a tall wall that can’t be climbed over. This is where your environment for the level begins to take form. While in the “blockout” process you are creating the size of the environment and the scale of the objects in proportion to each other and to the character you will be using within the game. This is also why when working in the “blockout” process you always have to take into account the amount of playable area that you are leaving for your level and also how the gameplay implementation will work with the current layout of your brushes. The purpose of this process is NOT to have a completed level or a nice pretty fancy looking environment, this is a “prototype” a “rough draft” of your level. Nothing that you create in your “blockout” process will ever be final it will always change. Starting the process can get a little overwhelming at first because it does start off a little cluttered with shapes if you start adding in a lot at once. It just takes some time to organize the shapes and resize them to work how you want them to, but during this process is when you really start visually see your project, your idea, taking form.
As you can see there are some advantages to being able to have access to and learning how to use these BSP brushes within the editor. Aside from the obvious where they are a huge help to begin to create and visually see what you are trying to create from the idea that was in your head. Another major plus with these brushes is their ease of use that they have, you can resize them and scale them and move them around all so effortlessly within the editor. The advantage of being able to “blockout” your level using these brushes lets you build architecture dimensions within your environment, it will also give you the ability to be able to jump into your level and test your ideas and your gameplay implementation extremely quickly without having to worry about finishing all the fancy art work for it yet. These brushes are so essential in project building within Unreal, even though you will most likely never see a BSP brush in a final production level you will most definitely never see a final production level that didn’t start as a BSP brush from the beginning.
