This option makes the current layer behave like a decal, using its own opacity mask to control where it appears. 

The base material remains fully opaque—this does not switch the material to an opacity-mask mode. Instead of covering the entire surface, the layer only shows up where the mask allows, making it ideal for details like dirt splashes, leaks, stickers, or painted markings that sit on top of the material without replacing it. The mask gives precise control over where the decal is visible and where it stays hidden, resulting in clean, well-defined overlays.

When enabled, the albedo from the current layer is blended with the bottom layer using a multiply operation. This makes darker areas have more influence while lighter areas fade out, helping the layer blend naturally into the base material. It’s useful for effects like dirt, stains, or wear, where dark details should show while bright areas are reduced or removed.

This is another optimization technique that makes the top layer use the same displacement as the bottom layer. It helps keep the surface depth consistent between layers and avoids harsh or pixelated displacement, which is especially useful for effects like dirt or overlays that should follow the underlying surface shape. 

This uses the same peeling technique as in the single-layer material. It adds worn or peeling edges to the current layer, helping layered materials show damage or separation in a more natural and consistent way.  

This uses the same fake shadow technique as in the single-layer material. It adds subtle shadowing to give extra depth where layers meet, helping details feel more grounded without using real dynamic shadows. 

Height Blend Albedo (Bottom Layer → Current Layer)

This blends the albedo from the bottom layer into the current layer based on height information. Areas with lower height let the bottom layer show through, while higher areas favor the current layer, creating a more natural transition between layers. 

Height Blend Displacement (Bottom Layer → Current Layer)

This blends displacement from the bottom layer into the current layer using height information. It helps the surface depth transition smoothly between layers, making details like dirt, buildup, or wear follow the underlying shape without harsh steps or breaks.