The real-time terrain generation techniques based on Digital Terrain Model (DTM) have a high requirement to hardware. And in many practical applications there is no need to simulate the terrain of certain area. Also people want to generate various terrain with different shape characters in order to meet different requirements flexibly. At this time it is obviously uneconomical to still use the method based on DTM. For this reason

the paper studies the modeling approach to 3D fractal terrain using data as little as possible for the PC. The terrain belongs to the multiresolution model that has several levels of detail coexisting. The projection of viewpoint is regarded as reference point from which a small primitive data set is generated

and forms multiresolution triangle meshes which define the shape of terrain base. Then

iteration is done by midpoint displacement and triangle edge sub-division method. It can produce natural terrains with different shapes. The construction method of multiresolution base has solved“spatial continuity”and“temporal continuity”between areas with different level of detail and avoids holes and seams

at the same time it dose not need extra computing works. Additionally

the base has a expansibility and can be expanded to needed shapes. The experimental results show that the method is simple

rapid and suitable for real-time display.