Vertex Color
Per-vertex paintable mask channel
Also known as: Vertex paint · Vertex colour
Definition
Vertex color is per-vertex RGBA data painted directly onto a mesh and used as a mask channel in shaders — typically to blend between two materials (R = sand, G = grass, B = stone) on terrain or modular kit pieces. It costs nothing in memory beyond the mesh itself and lets level artists hand-blend texture variation without authoring new textures. The classic use case is terrain painting in UE5.
In production
Blender, Maya, and UE5 all support vertex paint, and density of vertices on the mesh determines paint resolution — heavily subdivided meshes give smoother gradients but cost more memory and vertex-processing time, so terrain meshes are often subdivided specifically to support finer vertex-colour blending. The classic use case is terrain painting in UE5's Landscape system, where up to four material layers blend via RGBA vertex colour channels. On modular kit pieces, vertex colour often drives a different use — darkening crevices for fake ambient occlusion, or masking a wetness/dirt layer that responds to gameplay state without a texture swap. A common mistake is forgetting that vertex colour needs to be preserved through the export pipeline; FBX exports from Maya can silently drop vertex colour channels if the export preset isn't configured to include them, causing a broken-looking blend once the asset lands in-engine.