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

Hi. have a question for VS(Viewer Selector) post-process program..

Hirejet John, modified 5 Years ago.

Hi. have a question for VS(Viewer Selector) post-process program..

Youngling Posts: 11 Join Date: 4/3/13 Recent Posts
Hi. i`m Hireget jone.

Hi. have a question for VS(Viewer Selector) post-process program..
I try to convert Delft3d output file(*-m.dat, *-m.def : nefis) to ascii file.

In manual, user can convert nefis file to ascii use to VS(Viewer Selector).
So, i have compare VS(Viewer Selector) result with Gui postprocess program result(quickplot).

In every time, water level and suspended sediment area output data are same to two post program.
But, U,V Velocity is not same.....
I`m not Reliability VS(Viewer Selector) UV result data.
(Applied another project, Quickplot data correct observation data.)

VS(Viewer Selector) program is not old version and my delft3d version is
i saw update note(release note ) and it`s not update VS(Viewer Selector) program, now.

how to solve a problem effectively?
I have to vitally use VS(Viewer Selector) program.

help me please...
Adri Mourits, modified 5 Years ago.

RE: Hi. have a question for VS(Viewer Selector) post-process program..

Yoda Posts: 1224 Join Date: 1/3/11 Recent Posts
Hi Hirejet,

The U and V velocities written to the map file are located in the velocity points. QuickPlot interpolates them to cell centres before plotting. VS produces the U and V velocities at the velocity points.