Viewing and editing high resolution terrain files and DEMs (digital-elevation-models) is a challenge due to the large number of mesh triangles. A 1024x1024 terrain without any LOD (level of detail) reduction is more than two million triangles that must be rendered each frame (2,097,152 triangles).
This really pushes current high-end computer hardware to the limit, especially if the terrain data must be designed to support dynamic updates at any frame with no LOD reduction. After all, it's quite pointless to edit a terrain that is forced to a lower level of detail since then you cannot see what you are editing. Many commercial game engine editors can drop as low as two frames-per-second on a C2Q-3GHz/8GB-1066/NV275 when editing a terrain of 1024x1024 with no LOD or materials.
TerreSculptor defaults to editing terrains in WorldSpace mode at the native non-LOD level with full terrain resolution, and includes two specialized methods of scene optimization to allow for editing higher resolution terrains.
A 3001x3001 full-resolution no-LOD digital-elevation-model terrain test in MapSpace mode:
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