Create a decal via a Decal Projector in URP

The Decal Projector component can project a Material as a decal if the Material uses a ShaderA program that runs on the GPU. More info
See in Glossary Graph with the Decal Material type.

Shader Graph with the Decal Material type

URP contains the pre-built Decal Shader (Shader Graphs/Decal).

Decal Material properties and advanced options.

Create custom Decal shaders

The pre-built Shader Graphs/Decal shader serves as a simple example. You can create your own decal shaders that render decals in a way that suits your project best.

To create a custom decal Shader Graph, select the Decal value in Material property of the shader target.

Enabling one of the following properties override the equivalent Lit Shader property on the surface of the Material.

To improve performance, pack data for different surface properties into a single texture. This way the shader performs fewer samples and Unity stores fewer textures.

For example, the following Shader Graph uses a normal mapA type of Bump Map texture that allows you to add surface detail such as bumps, grooves, and scratches to a model which catch the light as if they are represented by real geometry.
See in Glossary and a mask map to drive all properties in the shader. This decal is used for the damaged tarmac effect, and a hardcoded roughness value of 0 suites the use case.

The shader samples the mask and uses the color for setting the Ambient Occlusion values (Red channel), smoothness values (Green channel), Emission intensity values (Blue channel), and alpha values for the entire decal. Decals are often blended using single alpha values for all properties. The following image shows the mask map for the example tarmac cracks:

Example of mask map that packs Ambient Occlusion, Smoothness, Emission, and alpha values of a decal atlas into a single texture.