Bump Map

A bump map is a grayscale texture that encodes height information across a surface. The shader uses it to perturb surface normals so light responds as if the surface had small bumps and dents, even though the geometry stays flat. It is a lightweight way to suggest fine relief.

The renderer interprets the grayscale values as a height field and tilts the shading normals accordingly, brightening apparent high points and shading low points. Because only shading changes, the actual mesh and its silhouette remain unchanged.

A bump map is grayscale and stores only height, while a normal map is RGB and stores full surface direction. The normal map responds to light more accurately from any angle and is the modern standard, whereas bump maps are simpler and older.

Both use grayscale height data, but a bump map only fakes relief through shading and leaves the silhouette flat, while a displacement map physically moves geometry to create real depth. Bump maps are cheaper; displacement changes the actual outline.

No. Like a normal map, a bump map only affects shading, so the actual mesh silhouette is unchanged. For real geometric relief you need a displacement map or added polygons.

Yes, for subtle, uniform relief such as grain or fine texture where a full normal map is unnecessary. In most modern PBR pipelines, though, normal maps have largely replaced bump maps because they are more accurate.

You convert an image to grayscale so that lighter areas read as raised and darker areas as recessed, then adjust contrast to control the strength of the relief. Tools like Photoshop, GIMP, and Substance can generate or refine a height map this way, and you feed it into your material's bump slot.

In Blender you plug a grayscale image into a Bump node and connect its output to the material's Normal input in the shader. The Strength value controls how pronounced the faked relief appears under lighting.

Meshy's generated PBR maps provide rich surface detail out of the box, and where a lightweight bump pass is enough the height data slots straight into your material. This lets you dial in subtle relief without authoring a full normal map.