intro story D-Flow FM


D-Flow Flexible Mesh

D-Flow Flexible Mesh (D-Flow FM) is the new software engine for hydrodynamical simulations on unstructured grids in 1D-2D-3D. Together with the familiar curvilinear meshes from Delft3D 4, the unstructured grid can consist of triangles, pentagons (etc.) and 1D channel networks, all in one single mesh. It combines proven technology from the hydrodynamic engines of Delft3D 4 and SOBEK 2 and adds flexible administration, resulting in:

  • Easier 1D-2D-3D model coupling, intuitive setup of boundary conditions and meteorological forcings (amongst others).
  • More flexible 2D gridding in delta regions, river junctions, harbours, intertidal flats and more.
  • High performance by smart use of multicore architectures, and grid computing clusters.
An overview of the current developments can be found here.
The D-Flow FM - team would be delighted if you would participate in discussions on the generation of meshes, the specification of boundary conditions, the running of computations, and all kinds of other relevant topics. Feel free to share your smart questions and/or brilliant solutions! 


We have launched a new website (still under construction so expect continuous improvements) and a new forum dedicated to Delft3D Flexible Mesh.

Please follow this link to the new forum: 

Post your questions, issues, suggestions, difficulties related to our Delft3D Flexible Mesh Suite on the new forum.





Sub groups
D-Flow Flexible Mesh
Cohesive sediments & muddy systems


Message Boards

No observation points = No run

Alexis Espinosa, modified 7 Years ago.

No observation points = No run

If I do not use two observation points my run does not pass from the Initialization stage part VI!!!
It simple gets frozen there and does not run at all.
After struggling with that, I thought this was a bug.

Later on, I found that the manual says that at least two observation points are needed. This is a bit weird!! Why is this??

It also says that when defining cross sections, two cross sections should be defined. This is also weird, although it seems that a single cross section works fine. Am I correct?

These are just small details, but a bit confusing for a beginner who passed one day figuring out this weird restriction!!

Adri Mourits, modified 7 Years ago.

RE: No observation points = No run (Answer)

Yoda Posts: 1221 Join Date: 1/3/11 Recent Posts
Hi Alexis,

I agree it's weird. This is one of the historical artifacts that needs to be removed. Unfortunately it does not have a priority.


mercy varghese, modified 7 Years ago.

RE: No observation points = No run

Youngling Posts: 17 Join Date: 8/6/13 Recent Posts

I know this is a very late post...... but what I have noticed is that if you run the batch file created using Dash don't need observation points.