The Stage Builder is a feature in Super Smash Bros. Brawl that allows players to create their own custom stages. Builders must choose to create a small, medium, or large stage, which will affect the number of parts that can be placed and the location of blast lines. Next, the builder selects a theme: a mountain backdrop, a big ruin-ish building on background, or a futuristic chamber. Each theme has its own set of special stage elements which allow for slight variations in stage design depending on what theme is used. The final step before building is picking a song, which can be any track that has been unlocked (but only one song may be used per stage). Then, set the terrain. There are different structures and building materials the player can use depending on the background chosen earlier. There are three different sizes for most of the structures, also. The player, however, is limited in the number of parts they can use per stage. Each piece used will use up so much memory for the map, and some pieces take up more memory than others. Once ready, the player can test the stage through the editor (you can only use Mario though), then switch back to the editing screen if they want to make any more changes. The player can send one stage per day to Nintendo. In addition, Nintendo will offer a "stage of the day" that players can battle on for one day only. The player can also send stages to your friends, and they are compatible with SD cards. The player can only have as many custom stages as however much room you have in your internal Wii memory and SD card.
Types of parts the player can use in this mode range from standard pieces, like blocks and ramps and stairs, to structures, like, ferris wheels, trees and mushrooms and rock arches, to features, like the Drop Blocks, which begin falling if stepped on long enough. Drop Blocks eventually respawn, and can only be activated from above, making it possible to make one-way doors of a sort. However, drop blocks will drop if items are spawned on them. To get the true effect of a one-way door, one must turn off items. There are also ice blocks. Walking/running on them is slippery, and there is high chance of tripping. Also the ledges can't be grabbed, which may lead to deaths if not aware of this.
In addition, this mode comes packed with interactive terrain objects. For example, players can make platforms that will move up or down, or side-to-side. This will create many options for map makers. There are also "traps," like spikes for example, that can be implemented into the map. Ultimately, in this mode you are limited by the player's own level of creativity (and memory usage). Many people have even modeled stages after Super Smash Bros. (Nintendo 64) and Super Smash Bros. Melee stages.
The Stage Builder is often used to get CDs and stickers. This is known as the CD Factory.
There are also certain parts and features that can be unlocked to use in the Stage Builder. There must be an opening in your stage to fall out of in order to unlock parts A,B, and C. In other words, you can't make 15 CD factories and expect to unlock Edit Parts C. You must exit out of stage builder when you're done to unlock the challenge.
- Edit Parts A: Play 10 times or more on stages you made.
- Edit Parts B: Create 5 or more stages in stage builder (not including the 3 sample stages).
- Edit Parts C: Create 15 or more stages in stage builder (not including the 3 sample stages).
- The futuristic chamber background is similar to the background in the Subspace Emissary's Research Facility II where players fight the two False Samuses or when Samus first encounters Ridley. Similarly, the ruins background can be seen in the distance behind part of The Ruins.
- When Crates and Barrels appear in a stage builder stage, they are always the Wooden ones.