Decal
Projected texture detail on existing surfaces
Definition
A decal is a texture (with alpha) projected onto existing geometry to add detail without retexturing the underlying surface — bullet holes, blood splatters, graffiti, scorch marks, signage. Decals decouple wear and storytelling detail from base materials, letting one neutral wall texture host hundreds of unique surface stories at runtime. Used everywhere in modern game environments to break up modular kit repetition.
In production
UE5 Decal Actors project a decal material onto whatever surfaces fall within the projection box, and support Deferred Decals that can modify base colour, normal, roughness, and even emissive independently, useful for everything from bullet impacts to glowing terminal screens. Mesh decals (small mesh planes textured with a decal material, offset slightly from the surface with a small Z-fighting bias) are an alternative with more control over which surfaces receive the decal, and are cheaper on mobile where deferred decal projection is unsupported or expensive. A common pitfall with projected decals is "decal bleeding" onto unintended geometry — a bullet-hole decal projected through a thin wall can appear on the opposite side unless the projection box is sized tightly. Substance Painter and Quixel Mixer are the standard authoring tools for decal textures, exporting a base colour/normal/opacity set that then gets tiled across a decal atlas to reduce draw calls.
Learn Decal in
Tools that use Decal
See also
Modular Kit
Reusable building blocks for environments
Texture Atlas
Multiple assets, one texture
Shader Graph
Visual shader authoring
Blend Mode
How a material combines with what is behind it
Hard Edges Where Smoke Meets Geometry
Visible cut lines where a sprite intersects a surface
Environment Looks Repetitive
Copy-pasted props and visible tiling