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

Boundary conditions coordinates invalid

Jeff Wilson, modified 6 Years ago.

Boundary conditions coordinates invalid

Youngling Posts: 5 Join Date: 11/22/13 Recent Posts

I am fairly new to Delft3D, and am having some issues setting up my boundary condition locations. First I tried using the visualization screen, but each time I try the GUI crashes. Second, I tried manually inputting the 'M' and 'N' locations on my grid, but each time get the error that my boundary coordinates are invalid. Wasn't sure if people have had similar problems, and if the issue was with the grid file or a bug in the GUI?


Adri Mourits, modified 6 Years ago.

RE: Boundary conditions coordinates invalid

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

The GUI is not supposed to crash when adding open boundaries. Can you mail me:
  • Actions to do to reproduce the problem
  • All input files needed to reproduce the problem
  • What Delft3D-GUI version you are using
  • What operating system you are using

Thanks in advance.

Adding open boundaries is a delicate thing. That's when the GUI becomes useful to guide you through. Solving the crash is the best way to proceed.