methods are often used for "stand-alone" moving objects, possibly including complex animation methods. A different approach is used for geomipmapping, a popular terrain rendering algorithm because this applies to terrain meshes which are both graphically and topologically different from "object" meshes. Instead of computing an error and simplify the mesh according to this, geomipmapping takes a fixed reduction method, evaluates the error introduced and computes a distance at which the error is acceptable. Although straightforward, the algorithm provides decent performance. A discrete LOD example As a simple example, consider a sphere. A discrete LOD approach would cache a certain number of models to be used at different distances. Because the model can trivially be procedurally generated by its mathematical formulation, using a different number of sample points distributed on the surface is sufficient to generate the various models required. This pass is not a LOD-ing algorithm. To simulate a realistic transform bound scenario, an ad-hoc written application can be used. The use of simple algorithms and minimum fragment operations ensures that CPU bounding does not occur. Each frame, the program will compute each sphere's distance and choose a model from a pool according to this information. To easily show the concept, the distance at which each model is used is hard coded in the source. A more involved method would compute adequate models according to the usage distance chosen. OpenGL is used for rendering due to its high efficiency in managing small batches, storing each model in a display list thus avoiding communication overheads. Additional vertex load is given by applying two directional light sources ideally located infinitely far away. The following table compares the performance of LOD aware rendering and a full detail (brute force) method. Hierarchical LOD Because hardware is geared towards large amounts of detail, rendering low polygon objects may score sub-optimal performances. HLOD avoids the problem by grouping different objects together. This allows for higher efficiency as well as taking advantage of proximity considerations. Practical applications Video games LOD is especially useful in 3D video games. Video game developers want to provide players with large worlds but are always constrained by hardware, frame rate and the real-time nature of video game graphics. With the advent of 3D games in the 1990s, a lot of video games simply did not render distant structures or objects. Only nearby objects would be rendered and more distant parts would gradually