ymap and ytyp Guide - Map Modding Basics in GTA 5 2026

Understanding ymap and ytyp Files

The ymap and ytyp file formats are the foundation of map modding in GTA 5. These binary files define how the game world is constructed — from building placements and road layouts to vegetation distribution and interior definitions. In 2026, understanding these formats is essential for anyone looking to create custom locations, modify existing areas of Los Santos, or build entirely new map content for single-player and FiveM multiplayer servers.

What is a .ymap File?

A .ymap (Yet another MAP) file contains map entity placement data. Each ymap defines a collection of objects positioned in the game world with specific coordinates, rotation values, and LOD (Level of Detail) assignments. The game loads ymap files based on the player's location, streaming nearby map data and unloading distant regions. Each ymap covers a specific geographic area and includes references to the 3D models (archetypes) that should be placed within it. Think of ymaps as the blueprint that tells the engine where to put everything.

What is a .ytyp File?

A .ytyp (Yet another TYPe) file defines object archetypes — the templates that describe what each placeable object looks like and how it behaves. While ymap files say "place object X at coordinates Y," ytyp files define what "object X" actually is. Each archetype entry includes the model name, physics bounds, texture dictionary reference, LOD distance, and special flags. When creating custom map objects, you must define their archetypes in a ytyp file before they can be placed via ymap.

Creating Custom Map Modifications

To create map mods, you need CodeWalker — the primary tool for editing ymap and ytyp files in GTA 5. CodeWalker provides a 3D viewport where you can place, move, and rotate objects in the game world. The workflow involves loading existing map data, making modifications or adding new objects, and exporting the changes as new ymap files. For custom objects, you first create the 3D model, define its archetype in a ytyp file, then place instances of it using ymap entities.

Map Streaming and Performance

GTA 5's map streaming system in 2026 divides the world into grid cells, each covered by one or more ymap files. When adding custom map content, proper streaming configuration ensures your additions load and unload correctly as players move through the world. Each ymap has a streaming extents definition that tells the engine when to load it. Overlapping or improperly configured extents can cause objects to pop in and out unexpectedly. For large map modifications, splitting content across multiple ymaps improves streaming performance and prevents memory issues.