Fixing Error x3004 in UE4 for Deferred Decal Materials (4.23)

2 min readDec 24, 2019

In version 4.23 of Unreal Engine, you will most likely be presented with “/Engine/Generated/Material.ush(1964,56–152): error x3004: undeclared identifier ´TextureExternalSample_Decal`” if you try to sample a Media Texture in a Material configured for Deferred Decals with a Translucened Blend Mode.

To work around this issue, we’ve found, that configuring the Sampler Node to consider Mip Map Level Inputs and overriding the default Level with 0, the material compiles without any issues.

Originally published at on December 24, 2019.