Search TipsDelaunay Algorithm
SIS Desktop will use a Delaunay algorithm 
for TIN creation when the Create TIN function is used (unlike the TIN from Polygon function which will generate a simple surface).
Delaunay algorithms minimize the sum of all angles in all triangles in the triangulation.
Conditions for a Delaunay triangulation:
-
Two opposing angles should have a sum of < 180°.
- The circumcircle of each triangle in the TIN does not contain the vertex of another triangle.
If both these conditions are not met, the algorithm will flip the common edge of two triangles in order to minimise the sum of all angles and ensure that both circumcircles are empty.
