Abstract: Plural levels of detail of a terrain are stored in memory in regular grids. In one such example, a terrain is cached in a set of nested regular grids obtained from the plural levels as a function of distance from a viewpoint. In one such example, the plural levels of detail of terrain comprise terrain elevation and texture images. If the viewpoint moves relative to the terrain, the nested regular grids are incrementally refilled relative to the viewpoints movement in the terrain. In one such example, a transition region is introduced to help blend between grid levels. The regular grids are stored as vertex buffers in video memory in one example. In one such example, a vertex data includes an elevation values from another grid level for efficient grid level boundary blending.