When optimizing 3D models, normal maps help by simulating high-detail surface textures without increasing polygon count.
Normal maps store surface normal direction information in texture form, tricking the lighting system into rendering the illusion of depth and detail. This reduces reliance on high-polygon geometry, lowering model file size and rendering load while preserving visual complexity.
In scenarios like real-time games or mobile applications with strict polygon limits, normal maps effectively balance visual quality and performance.