Your point cloud is too dense in some parts and this defeats the interpolation. I would suggest that you clean it up by discarding a few points, at least those which are very close with different altitudes. Anyway, here is the result for the simple Delaunay Triangulation. [image: 6pCj_TerrainCheylardtriangulation.png] A little bit shaky, but enough to extract isocontours and generate the terrain with a quadmesh style. [image: Rgej_TerrainCheylardquadmesh.png] Both are enclosed in the attached model (SU2017). terrain Cheylard - triangulation.skp Fredo