Roughness Map

A roughness map is a grayscale texture in a PBR material that describes microsurface detail, meaning how rough or smooth each part of a surface is. Dark values produce smooth, mirror-like reflections while bright values scatter light into soft, matte highlights. It is one of the most important maps for believable materials.

It controls how sharp or diffuse a surface's reflections are. Smooth areas, stored as dark values, reflect crisply like polished metal, while rough areas, stored as bright values, scatter light into a matte look. This drives whether a surface reads as glossy or dull.

They are inverses of the same property. Roughness workflows treat bright values as rough and matte, while glossiness workflows treat bright values as smooth and shiny. Most modern PBR pipelines, including those in Unreal and glTF, use roughness.

No. Roughness controls how sharp reflections are, while the metallic map controls whether a surface behaves as a metal or a non-metal. They are separate maps that work together to define a PBR surface.

You can author a roughness map in a texturing tool like Substance Painter or Photoshop by painting grayscale values where dark is smooth and bright is rough, often masking wear, fingerprints, and moisture. You can also derive it from surface photos or generate it as part of an AI PBR set.

In Blender you plug the roughness image texture into the Roughness input of the Principled BSDF shader and set its color space to Non-Color so the values are read correctly. The map then modulates gloss across the surface.

The most common cause is loading the roughness texture as sRGB color data instead of non-color, or linear, data, which skews the values. Setting the correct color space and confirming the roughness and glossiness convention match your engine usually fixes it.

Real surfaces are rarely uniformly shiny; edges wear, fingerprints smudge, and moisture pools. Varying roughness across a single object, such as scuffed edges on polished metal, communicates age and material in a way flat gloss cannot, which sells realism instantly.

Yes. Meshy generates roughness maps as part of its PBR output, so AI-textured models react to light with convincing gloss and wear the moment you import them. No manual roughness authoring is required to get a believable surface.