When creating lightmaps, any lighting model may be used, because the lighting is entirely precomputed and real-time performance is not always a necessity. A variety of techniques including ambient occlusion, direct lighting with sampled shadow edges, and full radiosity bounce light solutions are typically used. Modern 3D packages include specific plugins for applying light-map UV-coordinates, atlas-ing multiple surfaces into single texture sheets, and rendering the maps themselves. Alternatively game engine pipelines may include custom lightmap creation tools. An additional consideration is the use of compressed DXT textures which are subject to blocking artifacts – individual surfaces must not collide on 4x4 texel chunks for best results.