LOD is short for Level of Detail, and adjusting the LOD Bias is a method of sharpening details on textures. The LOD Bias controls texture detail by determining when different Mipmaps are used. Mipmaps are a precomputed series of textures each of a certain resolution used to improve performance. When you look at a surface close to you, a higher resolution mipmap is loaded; as you move further away from that surface, progressively lower resolution mipmaps of it are displayed instead. The default LOD Bias in a game is typically 0.0, but by using a negative value for LOD Bias (e.g. -1.5), you can force mipmap levels to be moved further away, which can improve texture sharpness at the cost of introducing shimmering when textures are in motion. In general, it is better to just use Anisotropic Filtering to improve texture detail, rather than lowering LOD Bias, as there is no shimmering and the performance impact is minor.