Assets

Everything you build a game from, meshes, textures, materials, prefabs, levels, is an asset. This section covers what assets are, how to organize and change them safely, how they point at each other, and how they are packaged for a shipped game.

What an asset is

An asset is a piece of saved content. On disk it is a single .lasset file under your project’s content folder. You never edit a .lasset by hand, you create and edit assets through the editor.

A .lasset file is a package. Most packages hold exactly one asset, which is why “asset” and “file” usually mean the same thing in practice. Some hold more: a material also stores its node graph inside its own package, a skeletal mesh import can bring a skeleton along. Those extra objects belong to the package and travel with it, they are not separate files you manage.

Identity: assets are found by id, not by path

This is the single most important thing to understand about managing content.

Every asset carries a GUID, a stable id assigned when it is created and stored inside the file. When one asset references another, it stores that id, not the path. The path is a label for humans and for the Content Browser.

Two consequences follow, and they drive almost every rule on the Managing Assets page.

• Renaming and moving an asset is safe. Everything pointing at it keeps working, because nothing was pointing at the old path in the first place.
• Copying a .lasset file outside the editor is not safe. The copy carries the same id as the original, and the engine treats an id as belonging to one asset. Use Duplicate in the Content Browser instead, which mints a new id.

Content paths

Assets are addressed by content path, not by where the project sits on your drive. The first segment of a path is a mount.

Mount	Points at
/Game	Your project’s Game/ folder.
/Engine	The engine’s built-in content.
/Config	Your project’s config.
/Intermediates	Generated intermediate files.
/<PluginName>	Content shipped by an enabled plugin.

Your own content lives under Game/Content/, so its paths start with /Game/Content/. The asset at Game/Content/Meshes/Cube.lasset is addressed as:

/Game/Content/Meshes/Cube

Note that the content path has no .lasset extension. The extension is part of the file name, not part of the asset’s address.

Because everything is addressed through a mount, paths keep working no matter where the project lives on disk, and a packaged game resolves the same paths it used in the editor.

Asset types

The asset types you will work with.

Right-clicking in the Content Browser offers a New Asset menu grouped by category. These are the types it can create.

Category	Assets
World	World, a level. Texture.
Mesh	Geometry Collection, pre-fractured pieces for destruction.
Material	Material, Material Instance, Material Function. See Materials.
Textures	Texture Array.
Render Target	Render Target, a texture the renderer draws into.
Animation	Animation Graph, Animation Montage, Blend Space, Sequence.
Physics	Physics Material (friction, restitution, density), Physics Asset (bodies and joints for ragdolls), Collision Shape.
Effects	Particle System.
Audio	Audio Stream.
Data	Data Asset, Data Table, Curve.
Gameplay	Prefab, a saved entity hierarchy.
UI	Font.

Some asset types are not created from scratch but come in through importing:

Asset	Comes from
Static Mesh	A model with no skinning.
Skeletal Mesh and Skeleton	A rigged model.
Animation	One clip per animation in the source file.

Textures, fonts, and audio can be either created empty or imported.

Files that are tracked but are not assets

Some loose text files are tracked so that references to them survive a rename: RmlUi documents (.rml) and stylesheets (.rcss). They are not packages, so they get their id from a hidden sidecar file stored beside your content. Treat them like assets when moving things around, and let the editor do the moving.

C# scripts are not tracked this way. They are compiled by the scripting host rather than referenced as assets. See Scripting.

The life of an asset

1. Created by a factory in the Content Browser, or imported from a source file. See Importing.
2. Edited in its asset editor, which marks it as having unsaved changes.
3. Saved to its .lasset. See Managing Assets.
4. Referenced by other assets, by components, and by scripts. See Referencing Assets.
5. Cooked into a shipped build, following those references to decide what gets included. See Cooking & Packaging.

The asset registry

The editor keeps an index of every asset in your project, built by reading file headers without loading the assets themselves. That index is what makes the Content Browser instant on a large project, and it is what knows which assets reference which.

You do not interact with the registry directly, but it is the reason the editor can answer “what uses this?” before anything is loaded, which is what makes safe deletes and reference replacement possible.

For the implementation, see Assets in Engine Internals.

In this section

• Importing, bringing in models, textures, and fonts.
• Managing Assets, saving, renaming, deleting, and doing it safely.
• Textures, color space and compression.
• Referencing Assets, pointing at assets from components and scripts.
• Cooking & Packaging, building a shipped game.