Vertex relocation: a feature-preserved terrain rendering method for pervasive computing environments

Recent days, real-time 3D visualization is widely required for pervasive games. Despite the use of level-of-detail techniques, the real-time rendering of massive terrain datasets exceeds the capability of today's graphics hardware. So, to visualize the realistic terrain on various devices, the oversimplification of datasets is required. The oversimplification reduces computing and data transmission time. Owing to the oversimplification, however, artifacts such as geo-popping may appear in rugged regions, particularly when low level-of-detail is involved. Geo-popping is undesirable visual effect that occurs when the transition of a 3D object to a different level of detail is performed. To reduce such artifacts, we propose a novel mesh simplification method by concentrating on the vertices of regular grids in a rugged area using the concept of attraction and elastic forces. Each sampling point of the terrain data may pull on adjacent vertices with an attraction force that corresponds to its predicted surface roughness. However, strong attraction forces may cause a geometrical twisting or overlapping problems. To solve these problems, we apply an elastic force to a vertex and its neighbors. This makes each vertex push its neighbors away when they are too close. Computing the displacement of each vertex using attraction and elastic forces provides a fine-mesh terrain representation in rough areas, and a coarse-mesh representation in smooth areas. As a result, our method efficiently visualizes more accurate terrain scenes by reducing the number of geo-popping that mainly appear in rugged areas.