so a large number of them must be used to approximate curves in a visually appealing manner. The use of complex models has a cost in lowered speed. In scanline conversion, each polygon must be converted and displayed, regardless of size, and there are frequently a large number of models on the screen at any given time. Often, programmers must use multiple models at varying levels of detail to represent the same object in order to cut down on the number of polygons being rendered. The main advantage of polygons is that they are faster than other representations. While a modern graphics card can show a highly detailed scene at a frame rate of 60 frames per second or higher, surface modelers, the main way of displaying non-polygonal models, are incapable of achieving an interactive frame rate (10 frame/s or higher) with a similar amount of detail. With sprites, another alternative to polygons, every required pose must be created individually, while a single polygonal model can perform any movement if the appropriate motion data is applied, and can be viewed from any angle. File formats A variety of formats are available for storing 3D polygon data. The most popular are: .3ds, .max, which is associated with 3D Studio Max .blend, which is associated with Blender .c4d associated with Cinema 4D .dae (COLLADA) .dxf, .dwg, .dwf, associated with AutoCAD .fbx (Autodesk former. Kaydara Filmbox) .jt originally developed by Siemens Digital Industries Software; now an ISO standard. .lwo, which is associated with Lightwave .lxo, which is associated with MODO .mb and .ma, which are associated with Maya .md2, .md3, associated with the Quake series of games .mdl used with Valve's Source Engine .nif (NetImmerse/gamebryo) .obj (Wavefront's "The Advanced Visualizer") .ply used to store data from 3D scanners .rwx (Renderware) .stl used in rapid prototyping .u3d (Universal 3D) .wrl (VRML 2.0) See also Finite element method Mesh generation Polygon (computer graphics) Polygon mesh Vector graphics Geometry processing 3D modeling References Bibliography OpenGL SuperBible (3rd ed.), by Richard S Wright and Benjamin Lipchak OpenGL Programming Guide: The Official Guide to Learning OpenGL, Version 1.4, Fourth Edition by OpenGL Architecture Review Board OpenGL(R) Reference Manual : The Official Reference Document to OpenGL, Version 1.4 (4th Edition) by OpenGL Architecture Review Board Blender documentation: https://web.archive.org/web/20051212074804/http://blender.org/cms/Documentation.628.0.html Maya documentation: packaged with Alias Maya, http://www.alias.com/eng/index.shtml 3D computer graphics