About Delos

Delos has been developped at the E.N.S.M.P since 1994 by O.Stab. It has been integrated in many FEM codes : VIPLEF, METIS, MELODIE  (I.R.S.N) and CAST3M (CASTEM 2000). It is used at the Geosciences Center of the E.N.S.M.P and in many companies : I.R.S.N, G.D.F, Geostock...

Delos can be used in many applications not only in FEM codes : for example it can be usefull to mesh a boundary of a 3D polyhedron, or for the computation of a topographic surface from elevation points coordinates...


Delos is based on a Delaunay's incremental algorithm ; very classic but robust (even in simple precision). It is followed by an edge forcing process. For more details you may consult my courses :  "modélisation & algorithmique géométrique" (only in french sorry).
For the moment Delos is not suitable for very big mesh (> 1M points).

Development, portability, accuraccy & robustness 

Delos is written in Fortran 77 ANSI. It has 3 main modules and many subroutines so it can be easily integrated in another software. The code has been tested on several architecture including : Window, Linux but also HP-UX, IRIX, AIX... Delos works well in simple precision but you may, if you need, transform the code in double precision by a trivial substitute command.

Future work

My goal is not to make Delos becoming a complete pre-processing software but just to make it more practical. So three main improvements are planned for the next release :
  1. As you have noticed no visualization software is proposed with Delos. From my point of view it is useless because there are so many on the web. Unfortunatly the actual output file format  is not suitable for these sofwares but I shall propose soon two standards : vrml (that can be displayed with SIM vrmlview) and gts format (GNU triangulated surface).
  2. Delos result is a file containing a list of triangles (3 nodes for the moment) but FEM simulation often need accurate elements like quadratics (6 nodes triangles). The improvement is quite simple.
  3. Delos deal with simple geometries made of straight edges only. As one of my collegue says; it will be smart to add arc of ellipse. I shall cause it won't take to much time anyway.
These improvements are easy to do so if you are in hurry you can do them by yourself by modifying the source code. If you have time just wait for the next release.