not necessarily topology Displace - Introduce additional geometry based on a "displacement map" from the surface Simplify - Systematically remove and average vertices Subdivide - Introduce new vertices into a mesh by subdividing each face. In the case of, for instance, Catmull-Clark, subdivision can also have a smoothing effect on the meshes it is applied to. Convex Hull - Generate a convex mesh which minimally encloses a given mesh Cut - Create a hole in a mesh surface Stitch - Close a hole in a mesh surface Measurements - Compute some value of the mesh Volume - Compute the 3D volume of a mesh (discrete volumetric integral) Surface Area - Compute the surface area of a mesh (discrete surface integral) Collision Detection - Determine if two complex meshes in motion have collided Fitting - Construct a parametric surface (NURBS, bicubic spline) by fitting it to a given mesh Point-Surface Distance - Compute distance from a point to the mesh Line-Surface Distance - Compute distance from a line to the mesh Line-Surface Intersection - Compute intersection of line and the mesh Cross Section - Compute the curves created by a cross-section of a plane through a mesh Centroid - Compute the centroid, geometric center, of the mesh Center-of-Mass - Compute the center of mass, balance point, of the mesh Circumcenter - Compute the center of a circle or sphere enclosing an element of the mesh Incenter - Compute the center of a circle or sphere enclosed by an element of the mesh Extensions Once a polygonal mesh has been constructed, further steps must be taken before it is useful for games, animation, etc. The model must be texture mapped to add colors and texture to the surface and it must be given a skeleton for animation. Meshes can also be assigned weights and centers of gravity for use in physical simulation. To display a model on a computer screen outside of the modeling environment, it is necessary to store that model in one of the file formats listed below, and then use or write a program capable of loading from that format. The two main methods of displaying 3D polygon models are OpenGL and Direct3D. Both of these methods can be used with or without a 3D accelerated graphics card. Advantages and disadvantages There are many disadvantages to representing an object using polygons. Polygons are incapable of accurately representing curved surfaces,