External memory management and simplification of huge meshes

Very large triangle meshes, i.e. meshes composed by millions of faces, are becoming common in many applications. Obviously, processing, rendering, transmission and archival of these meshes are not simple tasks. Mesh simplification and LOD management are a rather mature technology that in many cases can efficiently manage complex data. But only few available systems can manage meshes characterized by a huge size: RAM size is often a severe bottleneck. In this paper we present a data structure called Octree-based External Memory Mesh (oemm). It supports external memory management of complex meshes, loading dynamically in main memory only the selected sections and preserving data consistency during local updates. The functionalities implemented on this data structure (simplification, detail preservation, mesh editing, visualization and inspection) can be applied to multi-Giga triangles meshes on low-cost PC platforms. The time overhead due to the external memory management is affordable. Results of the test of our system on complex meshes are presented.