Polygonal Models Decimation

When representing objects with polygonal models, we must often use models consisting of large number of polygons. If we want to work in real time with such model the model must be simplificated. The process of simplification is called decimation. We know several decimation techniques for simplification of models. According to characteristics of model and target features of simplified model, we want to choose suitable method. So we need to know characteristics of particular methods and also their limits