Asset References

Path(…) is how source code names an existing Unreal asset: a package root plus a relative path, resolved to a full object path at generation time.

Path( <root> , "<relative-path>" )
Path( "<absolute-path>" )
"<absolute-path>"

Texture2D A = Path(Game, "Textures/T_X");
Texture2D B = Path("Plugin.MyPlugin", "Textures/T_X");
Texture2D C = Path("/Game/Textures/T_X");
Texture2D D = "/Game/Textures/T_X";              // bare quoted form

The root may be written quoted or bare. The bare quoted path form arrived in since 1.5.0; the Plugin. / Plugins. roots have existed since since 1.2.0.

You will meet Path(…) in four places:

Roots

The root argument is unquoted, \ is folded to /, and leading and trailing / are stripped; the result is split on /. The first segment names the root.

All spellings are matched case-insensitively; any other first segment fails.

Segments after the root are appended as folders. Path("Game/Textures", "T_X") resolves to /Game/Textures/T_X, and Path("Plugin/MyPlugin/Materials", "MF_X") to /MyPlugin/Materials/MF_X.

A plugin root resolves through the plugin's own mounted asset path, normalized the same way (backslashes folded, trailing / stripped, a leading / added). If that path is empty or just /, /<PluginName> is used instead.

Object-path completion

After the root and the relative path are joined, the result is completed to a full object path: if the text after the last / contains no ., the asset name is appended after a ..

The completed path is finally validated by Unreal's own object-path validator, whose message is reported verbatim when it fails.

Two resolvers

There are two independent implementations with different accepted forms and different error text. Which one runs depends on where the reference appears.

Where they differ

String escapes

Quoted paths are string literals. Both resolvers recognize \n, \r, \t, \" and \\; any other \X yields the literal X. See Lexical Elements.

Loading is a separate step

Resolving a path produces text. Whether the asset then loads is a separate step, and the outcome depends on the slot:

Diagnostics

Texture-default resolver

Unreal's own object-path validation message is reported verbatim when the completed path is not a valid object path. The caller wraps every message above:

Asset-reference resolver

The complete cross-stage list is in Diagnostics.

Example

Shader(Name="Docs/M_Paths")
{
    Properties = {
        // Root + relative path — the canonical form.
        Texture2D A = Path(Game, "Textures/T_White");

        // Quoted root, and extra folder segments carried by the root.
        Texture2D B = Path("Game/Textures", "T_Noise");

        // Engine content.
        TextureCube C = Path(Engine, "EngineResources/DefaultTextureCube");

        // Plugin content: both spellings resolve identically.
        Texture2D D = Path(Plugin.DreamShader, "Textures/T_Probe");
        Texture2D E = Path("Plugins/DreamShader", "Textures/T_Probe");

        // Single-argument and bare quoted forms — both must be absolute.
        Texture2D F = Path("/Game/Textures/T_White");
        Texture2D G = "/Game/Textures/T_White";

        // The asset-reference resolver, reached through metadata.
        CurveAtlasRowParameter Row = float3(0.5, 0.5, 0.5) [
            Curve = Path(Game, "Curves/CV_Ramp");
            Atlas = Path(Game, "Curves/CA_Ramps")
        ];

        // The asset-reference resolver, reached through a UE builtin argument.
        UE.CollectionParam(Collection = Path(Game, "Collections/MPC_World"),
                           Parameter  = "WindStrength") Wind;
    }

    Settings = { Domain = "Surface"; ShadingModel = "Unlit"; BlendMode = "Opaque"; }
    Outputs  = { vec3 Color; Base.EmissiveColor = Color; }

    Graph = {
        Color = vec3(Wind, Wind, Wind);
    }
}

Resolved object paths:

A  /Game/Textures/T_White.T_White
B  /Game/Textures/T_Noise.T_Noise
C  /Engine/EngineResources/DefaultTextureCube.DefaultTextureCube
D  /DreamShader/Textures/T_Probe.T_Probe          (plugin mounted asset path)
E  /DreamShader/Textures/T_Probe.T_Probe
F  /Game/Textures/T_White.T_White
G  /Game/Textures/T_White.T_White

Next

• Property Types — which tokens accept = Path(…) and which do not
• Metadata and Groups — object-valued entries and the silent-null case
• Asset Paths — the output side: Name= + Root= → package path
• UE.* Nodes — UE.CollectionParam and its Collection argument