In surface modeling and solid modeling, the method used to represent 3D objects as a collection of triangles or other polygons. All surfaces, both curved and straight, are turned into triangles either at the time they are first created or in real time when they are rendered. The more triangles used to represent a surface, the more realistic the rendering, but the more computation is required.
Triangles Can Be Discarded
Depending on the object's distance from the camera, triangles may be discarded at the time they are rendered. Some applications create multiple models with different amounts of triangles and use the best one depending on distance. The vertices (end points) of the triangles are assigned X-Y-Z and RGB values, which are used to compute light reflections for shading and rendering.
For 3D Only
Tessellation is not used in 2D graphics. Although 2D graphics may be used to draw 3D objects, any simulation of depth and shading must be created by the artist using standard drawing tools, color fills and gradients. See surface normal
and graphics pipeline