Normalmappning

Normalmappning, or normal mapping in English, is a technique used in 3D computer graphics to add fine surface detail to a model without increasing polygon count. It works by encoding the surface normal vectors in a texture, known as a normal map. During rendering, the graphics pipeline uses these encoded normals to perturb the lighting calculations, giving the impression that the surface has bumps, dents or other intricate features. The geometry of the model remains simple; all the added detail is achieved through the lighting calculation.

The normal map is generated by baking or painting the desired surface detail into a bitmap. Each pixel contains a vector in tangent space: the red channel represents the X component, green the Y component, and blue the Z component. Because the vectors are normalized, the values are typically stored in the range of 0‑255 and remapped to −1 to 1 during shading.

Normalmappning is especially useful for real‑time applications such as video games. It allows artists to produce high‑fidelity visual detail on low‑poly meshes like characters, vehicles or environmental objects, keeping performance within acceptable limits. The technique is also common in advanced rendering pipelines for movies, architectural visualisation and virtual reality, where the balance between visual quality and computational cost is critical.

There are several variants. Tangent‑space normal mapping is the most common; object‑space mapping uses world or object coordinates and requires less texture coordinate manipulation. Parallax occlusion mapping extends normal mapping by simulating depth and self‑occlusion, producing stronger depth cues.

While normalmappning increases photorealism, it has limitations. It only affects the appearance of lighting; it does not influence collision or physics. If the underlying mesh lacks the required topology for sharp features, normal mapping can produce artifacts such as unrealistic light spill or exaggerated shadows. Careful attention to texture resolution and mapping methodology helps mitigate these problems.