Kitbashing

Kitbashing means building something new out of parts that already exist. The term comes from scale modelling: Wikipedia defines it as "the practice of making a new scale model by taking pieces out of kits" (Wikipedia: Kitbashing). In 3D, Unity's creative director describes it as "combining different assets to create something original and new" (Unity Blog: Realizing rapid conceptual design with…).

For game artists the word covers three related practices: assembling scenes from pre-made asset packs, detailing models from an in-house parts library, and mixing modular kits to make new kinds of space. All three trade some originality per part for a lot of speed.

#From film models to game engines

Kitbashing became widely known through film and television effects work. Wikipedia names Thunderbirds, Star Trek, 2001: A Space Odyssey and Star Wars Episode IV: A New Hope, noting that "Many of the spaceship models created for these programs incorporated details from tank, speedboat and car kits" (Wikipedia: Kitbashing). Model makers bought plastic kits, cut them up and glued the pieces onto new hulls. The result read as complex, functional machinery because the parts came from real-looking machines.

Digital kitbashing follows the same logic with meshes. Companies such as KitBash3D, founded by art director and matte painter Maxx Burman with Banks Boutté, sell themed kits aimed at "concept artists, matte painters, illustrators, environment artists and VFX artists" so they can "quickly assemble 3d scenes" (ArtStation Magazine: Don't Wait to Create with KitBash3d). (That article is sponsored, so treat its speed claims as marketing.)

#Three kinds of kitbashing in games

#1. Asset packs for concepts and prototypes

Unity's 2020 demo shows the prototype use. The team built a greybox with basic lighting, then "subbed in the KitBash3D and Snaps assets" over it, splitting the work across three scenes so people could work in parallel (Unity Blog: Realizing rapid conceptual design with…). They argue kitbashing lets teams "produce prototypes and polished final projects much more quickly" (Unity Blog: Realizing rapid conceptual design with…). The demo was an offline-rendered cinematic, so the team prioritised looks over optimisation (Unity Blog: Realizing rapid conceptual design with…); a shipping game would need more care with polygon and triangle budgets and draw calls.

#2. In-house parts libraries

Studios also kitbash with their own parts. On DOOM Eternal, environment artist Chase Long says kitbashing helped "keep visual continuity, save time", alongside a pipeline that relied heavily on "tiling materials and trim sheets" (80 Level: Designing Environments for DOOM Eternal). A shared library of vents, panels, pipes and bolts keeps rooms made by different artists visually consistent. This is common in hard-surface modeling, where small parts (sometimes called greebles) are dropped onto larger forms, and in the the mid-poly workflow. Santa Monica Studio's Jon Arellano notes in his God of War Ragnarök Asgard kit breakdown that many of the props were kitbashed, from pieces concepted and built by artists across several studios (ArtStation: God Of War Ragnarok - Kit Assets).

#3. Mixing modular kits

Level designers kitbash too. Joel Burgess uses the term for combining Skyrim's kits: a Dwemer example mixes a dwarven hallway with ice caves to change a space's tone (Game Developer: Skyrim's Modular Approach to Level Design). Skyrim also had "Platform" and "Glue" kits whose job was to connect other sub-kits and support this mixing (Game Developer: Skyrim's Modular Approach to Level Design). Kitbashing here is a way to reduce art fatigue: the same pieces, combined differently, produce spaces players haven't seen before. See modular kits.

The same happens in open worlds. On Hogwarts Legacy, Molly Warner of Certain Affinity lists kitbashing castle pieces among her tasks on an explorable castle ruin in Lower Hogsfield, alongside set dressing, terrain and foliage, and credits the Avalanche environment art team for the assets (ArtStation: Hogwarts Legacy - Castle Ruins). In this case one team built the kit and another assembled locations from it.

#Kitbashing guidelines

1. Match scale first. Parts from different sources rarely share a scale. Normalise them to your project's units before you combine anything.
2. Fix pivots. Unity's team used a mesh-combining tool to merge parts and set pivots at mesh level (Unity Blog: Realizing rapid conceptual design with…). Predictable pivots make parts easy to reuse.
3. Unify materials. A kitbashed asset looks inconsistent if each part has its own texel density, roughness range and colour palette. Re-texture parts with your project's master materials, trim sheets or texture atlases.
4. Hide the joins. For off-grid joins, The Level Design Book's advice applies: let pieces intersect and cover "the messy intersection with another object" (The Level Design Book: Environment Art). Collars, brackets, cables, rubble and decals are common ways to hide seams. Watch for Z-fighting where faces overlap exactly. EMC3D's breakdown of Hogwarts Legacy has a chapter on "crashing in geometry", intersecting pieces in a shipped open world (YouTube: Why Does Hogwarts Legacy Environment Art Look…).
5. Design the overall silhouette. The assembled silhouette should read as one designed object, with a clear primary form and smaller parts as secondary detail.
6. Merge for performance. Many small parts mean many objects; combine them into one mesh (or use instancing) once the design is settled.
7. Check the licence. Asset packs come with terms about redistribution, games and portfolios. See asset libraries and asset licences.

#Further reading and watching