TIN

A TIN (Triangulated Irregular Network) is used in surveying programs as a DEM (Digital Elevation Model) or DTM (Digital Terrain Model). It is called irregular because the number of edges incident at a point is not limited to six. The difference between a TIN in Bezitopo and a TIN in other surveying programs is that, in Bezitopo, the triangles are cubic surfaces, like Bézier splines with one more dimension.