Gameplay ideas rarely pan out the way you see them inside your head, making grayboxing one of the most important parts of the level design process.
Grayboxing (also known as the blockout stage) refers to the process of transferring your vision (or an existing prototype) into a simple but playable in-game version. It allows you to make great strides on playability and validate the base geometry before investing time dressing it up.
The titular gray box refers to the boxy, largely untextured look of levels quickly assembled in 3D editors:
A grayboxed (blocked out) level for a game in the Uncharted series, as shared by the level designer ...
