GTA 6 Map Modding and Custom MLOs

Custom interiors (MLOs) are what sets apart the best GTA RP cities: a custom police station, a custom MRPD, a custom apartment interior. In GTA 5 these are a mature art form. In GTA 6 they are unknowns. Let's break down what to expect.

What an MLO actually is

MLO is short for Map Location Object. Basically, it's a premade 3D interior that replaces or adds to the default game map. Good MLOs allow roleplayers to walk into a building, use the full interior, then leave seamlessly.

Constructing an MLO involves 3D modelling, texturing, collision setup, portal and room definitions, along with engine-specific exporting. It is typically not a single-person task if high quality is desired.

What will likely change in GTA 6

• New archive formats. GTA 5 files are stored in .rpf archives. GTA 6 is expected to use an updated archive format (referred to by community sources as .rpfx, unconfirmed). Existing export pipelines will require updates.
• Higher polygon budgets. Consoles have jumped from PS4 to PS5-class hardware. Plan for MLOs to be roughly twice as complex.
• Better lighting. Global illumination and real-time ray tracing will almost certainly be present in the engine. MLOs will require more attention to lighting than what GTA 5 necessitates.
• Updated physics and collisions. Small change, big impact. Your collision workflow will be different.

What will probably stay the same

• Room and portal systems. Every interior engine has variations of these.
• Basic 3D workflow for Blender or 3DS Max.
• Texture and material fundamentals.
• Reference and scale considerations.

This means your modelling and texturing skills will carry over. Your export/packaging workflow will not.

Should you start building GTA 6 MLOs now?

For reference/concept work, yes. Begin gathering reference imagery of Vice City-style architecture, layout sketches of interiors you want, material palettes, etc. This work can be done independently of engine changes.

Hold off on production export work. Any GTA 6 MLO that you model and export in April 2026 will need to be remade when the actual tools are released. Don't waste time exporting something that won't work.

Performance expectations

A well-built GTA 5 MLO takes up 3-6MB of VRAM and adds about 0.2ms of frame time. Expect GTA 6 to roughly double both of those numbers. Servers pushing 20+ custom MLOs are going to have to think harder about VRAM budgets and streaming, especially with players on minimum-spec consoles.

Our performance guide will have information on MLO budgeting when real GTA 6 metrics come out.

Legal considerations

This part is more important than most newcomers realise. Unlike custom vehicles (which have clear trademark issues), MLOs typically don't have as many legal barriers because they're original architecture. However:

• Avoid recreating real-world trademarked buildings exactly as they appear. Building a plain "police station" is acceptable. An exact replica of a real-world landmark with its real-world name is not.
• Credit the original artists if you use their textures or reference their material.
• Mind the licences of free asset packs. Some are CC0, some need attribution, some aren't for commercial use.

Related reading

For a general overview of the modding situation, see our GTA 6 modding tools overview. For custom vehicles specifically (which come with different legal considerations), see our custom vehicles planning guide. For scripting-related aspects of content creation, our RP server startup guide details the entire pipeline.